It's been almost exactly three years since I started Fitocracy with my partner Brian.

In that time period I've been everywhere from euphoric, depressed, broke, not-as-broke, in a serious relationship, single, in a serious relationship again, single again, sleeping 8 hours per day, sleeping 8 hours per week...

I suspect it's a decade's worth of life statuses and emotions.

Anyway, I thought it would be useful to brain dump the top 10 things I've learned across entrepreneurship and life. Here they are.

1. You can't change your character flaws.

Now this sounds a bit pessimistic, especially because self-improvement is my m.o., but here's what I mean – there are major aspects of your personality that are going to be relatively immutable. For example, I have little attention to detail. While I can improve this skill, it would be quite time consuming, and my attention to detail will never be great.

Far better would it be to embrace this flaw, then surround myself with people who make up for my weaknesses.

(EDIT: I'm admittedly using some circular logic here. I define "character flaw" as a characteristic that you can only marginally improve. The important part, of course, is to discover which one of your lagging skill sets qualify as a character flaw)

2. The combination of attention to detail and holistic thinking = The Holy Grail.

I've spent a lot of time recruiting, interviewing, and thinking about people and their personality. The combination of attention to detail and the ability to think holistically is the rarest of all gifts.

What's this person like? A brilliant strategist who can also pay attention to all of the minutia. My summer intern was one of these. She would make sure that Fitocracy blog posts were all flawless, but she could also think about distribution and positioning strategies around content.

This person is rare because the traits of "attention to detail" and "thinking holistically" are diametric opposites; there's a tension between these two characteristics. I've noticed that people can usually either see the trees or the forest, but not both.

If you find someone like this, keep them and don't let them go.

3. Don't trust grown women who still like Hello Kitty.

Just trust me on this one.

4. If you want to convince someone, don't ever argue.

As it turns out, the worst thing that you can do to convince a smoker to quit is factually lay out the risks – tell him about the health dangers of smoking, how long he has to live, etc. Basically what most doctors do.

That's because there's nothing that you can tell a smoker that he hasn't already struggled with internally. By trying to "convince" him, he'll only start clinging on to the opposite belief. People are funny creatures that way. Check out "the backfire effect" for more astonishing revelations on how people completely dismiss truth.

Getting people to change is one of the hardest things in the world. There's actually a whole discipline called motivational interviewing dedicated to getting people to simply open up to the possibility of change.

5. You don't know what you're doing. It's ok. Neither does anyone else.

If you know what you're doing, then you're probably doing something that's been done before.

If a group of people act like they know what they're doing or know exactly how an industry is going to unfold, then they're trapped in what's called a "circle jerk."

Don't circle jerk.

6. Broke does not equal unhappy.

The three most dangerous addictions in life are heroin, carbs, and a weekly paycheck. (Can't remember who said this. EDIT: Apparently this is a Taleb quote.)

Being broke sucks, but being unhappy sucks even more. I'm glad that I traded my cushy job and condo to move to the ghetto.

7. Classiness is overrated.

Yep, I said it. It's overrated.

Not caring about classiness has allowed me to be scrappy. Guess which trait is more valuable for a startup. Save classiness for your 30's... or after an exit.

8. Help people relentlessly and without agenda.

About a year and a half ago, I met someone by the name of Mallory Hagan. Mallory was a sweet, spunky, super intelligent young lady who needed a little help with her diet, training, and social media presence. She seemed incredibly determined, so I helped her as much as I could. At the time, Mallory was Miss New York City. She went on to win Miss New York and then Miss America less than a year later.

Think of a relationship as an investment. If you only network with people who are already valuable, you are constantly buying high. If you spend a lot of time relentlessly helping anyone who needs it, you'll end up meeting amazing people who end up being very loyal friends.

9. Cats are great.

They have the maintenance level of a plant and help you deal with the emotional roller coaster that is startups.

10. Haters are a metric of success.

If you aren't getting hate, you aren't crossing the chasm into the mainstream. You're either staying within the echo chamber, circle jerk, or even worse, you don't have an audience. While you shouldn't out hate, think of it as an indicator that you're doing something right.