Years ago, in my first laboratory job, I worked for a principal investigator I'll call Jake. At first, Jake seemed like a standard scientist; he devised experiments, discussed results, and taught me various lab techniques.

One day I used the last dregs of a 4-liter glass bottle of ethanol. I asked Jake what to do with the empty bottle, because it seemed too large to cram into the sharps container.

"It's not really empty," he explained with a smile. "There's ethanol residue coating the inside. That means we can do this." Then he set the bottle in the middle of the floor and dropped in a lit match. A column of flames shot nearly to the ceiling.

I realized I had a lot to learn from Jake. That day, for example, I learned to wear my lab coat. And protect my eyebrows.

Once the bottle had cooled, Jake picked it up. "We'd better hang on to this," he said. "We might need to put some more ethanol in the bottle and repeat the experiment tomorrow."

A few months later, Jake invited the whole lab to his house, where he showed off his collection of spears, a well-worn kickboxing dummy, and a workshop where he made his own high-caliber bullets -- you know, for boar hunting.

Now that I'm occasionally here, real progress can begin. --The Overconfident Undergrad

Best principal investigator ever.

I had always thought of scientists as serious, responsible people. A bit socially awkward, maybe, but certainly smart and probably boring -- the sort of folks you'd have dinner with and then tell your spouse, "Well, I didn't understand everything they were saying about tuberculosis, but in general they seemed pleasant." In reality, though, scientists are as idiosyncratic, incompetent, and irresponsible as people in any industry. We just have cooler coats.

Here are several categories of people you'll find working in labs. Do you recognize any of your colleagues in this list? If not, you know what that means: One of these people might be you.

The 12th-year grad student

For the 12th-year grad student, the most difficult part of writing a dissertation is, apparently, deciding to begin. This lab member -- who alternates between deciding to decide to begin and deciding to eat lunch -- has been in the lab so long that you suspect he's trying for tenure. In general, it's good to give people like this a chance to succeed independently, but it's also possible that the 12th-year grad student is waiting to get help from his own children when they're old enough to go to grad school.

The equipment hog

For some people, the idea of "sharing" lab equipment means, "I'll share some of the equipment I have today with myself tomorrow, and I'll do that by hiding it." Be especially careful if an equipment hog sequesters a permanent marker or label maker, as these are the means by which larger lab equipment can be annexed.

The fearless one who really ought to experience fear

Behold, the lab worker who is brash in the face of danger! Marvel as he defies death by reaching into containers of hot, cold, caustic, or carcinogenic material without the proper safety attire! Be amazed as he juggles not one, not two, but three simultaneous chemical reactions in delicate glassware, each of which ought to command his full attention! Stare aghast when he tells you that his own hands ought to count as a secondary container and asks whether "MSDS" is an operating system!*

The administrator who knows everything

If knowledge is power, then the most powerful person in any lab is the one in charge of ordering supplies, shipping packages, and generally keeping the lab running. Here are a few questions that the administrator who knows everything can typically answer within 5 seconds:

"I bought an Erlenmeyer flask in 1983. What was its catalog number?"

"What is the correct number of slices of pizza to order for a lab meeting, and why don't we order from that one place down the street anymore?"

"Who in the lab is pregnant?"

If you want to keep the administrator who knows everything busy for a week, simply ask, "Which person of elevated status do you have a strong opinion about?"

The overconfident undergrad

Everyone in the lab has been working on this project for decades, implies the overconfident undergrad with his cocksure demeanor and spotty laboratory attendance record, but now that I'm occasionally here, real progress can begin. Bored by manual labor and background reading, the overconfident undergrad instead provides offhand "solutions" to your problems -- none based on logic or science -- and appears to be constantly looking around the corner in anticipation of the arrival of his Nobel Prize Committee. Strangely, the overconfident undergrad loses all ambition as the semester progresses, and if the MCAT is less than a month away, he'll vanish completely.

The martyr

Nothing ever works for the martyr, and she wants everyone to know it. "I stayed in the lab until midnight last night," she'll say, "and then I added the wrong ingredient in step 33 and had to throw it all away." Well, ... don't do that.

The one who uses inappropriately exhilarating vocabulary

Science is science. It's not an extreme sport. But maybe some scientists would much rather be cliff diving -- that's the only possible explanation for the way they describe routine lab work. "Man," they'll say to no one in particular, "I rocked that experiment! The standard deviation almost slammed me, but I blasted it with a bitchin' double-shot of Mann-Whitney and demonstrated statistical significance like a champ! Then I calibrated the balls off of that spectrophotometer!"

The misinterpreter

"I want you to recheck your results from yesterday," you tell the misinterpreter, by which she thinks you mean, "I want you to begin a new, fun project." Then you say, "You should read the paper by Smith et al.," and she hears, "You should presume to already know the contents of the paper by Smith et al." The best way to rid your lab of a misinterpreter is to say, "I think you should stay here."

MacGyver

"Look at this scanning electron microscope I built out of toothpicks, baking soda, and a hairbrush!"

Involuntary MacGyver

"Look at this scanning electron microscope I built out of toothpicks, baking soda, and a hairbrush because I'm poorly funded!"

The one who pretends to be MacGyver

"Look at this scanning electron microscope I built out of two pieces of tape and a scanning electron microscope!"

The one who gets incredible results but only while unsupervised and exactly once

We all know that unambiguous lab results are the stuff of legend, and in fact we spend most of our time performing experiments to determine why our previous experiments failed. Thus, when someone's data points appear beautiful and noise-free, she may be the one who gets incredible results but only while unsupervised and exactly once. Much like Heisenberg's Uncertainty Principle, the very act of observation somehow perturbs the system, so you'll never witness her results actually occurring in the lab -- you'll just see a clean graph, a person who smilingly claims science is simple, and an R2 value disturbingly close to 1.**

The high school intern

Many companies and universities have recognized the value of hiring high school interns because, let's face it, those social media sites aren't going to covertly surf themselves. Full of fascinating questions, such as "Do I have to stay until 5:00?" and "Do you guys check our Web history?" high school interns ensure that every minute in your laboratory will include vivacity, enthusiasm, and five or six text messages.

The lab notebook catcher-upper

A good lab notebook is a crucial part of scientific record keeping, which is why the lab notebook catcher-upper really intends to write in one at some point. You'll find his desk littered with Post-it notes and paper towels covered in scrawls that he has foolishly promised himself to later expand into formal notebook entries, such as "Nov. 8 -- worked with machine, did test, got results" and "Apr. 22 -- science." He tends to be the same person who labels his lab samples with memorable names like "Sample 1" and "+."

The quiet guy who basically keeps to himself and maybe does something with computers or something

You know who I mean? That guy, in the back? I think he's from Asia or somewhere? He's been in the lab for years, but I haven't heard him speak. Doesn't he do something with computers? No, you go ask him.

And, of course, there are a few types of people you'll never see in a lab -- but you'd really, really like to. Such as:

The legitimately attractive person whom lab goggles make appear hot and smart

The traveler from the future who gives you hints about your research

The CEO or university president who still performs lab experiments manually

The daily brownie bringer

Jake. If he's still alive.

*Seriously, don't do these things, as such behavior can lead to injury or death. Always follow safety rules, and wear the necessary personal protective equipment. This footnote makes my editor happy.

**The sort of behavior described here is scientific misconduct, and it's very wrong. Don't do it. This footnote, too, makes my editor happy.