In my 18 years as a flight attendant, I've pretty much seen it all and then some, including a monkey seated in business class. She was on her way to the Today show, and even though all I served her on the five-hour flight was a cup of water, I'll never forget when her fingers reached through her cage to shake my hand.

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Some of my favorite passengers are animals. Did you know celebrity animals get their own seats? Not celebrity pets — no, I'm talking about animals that have made a name for themselves. Think Lassie, Benji, Grumpy Cat. Remember Spuds MacKenzie, the hard-partying bull terrier from the Bud Light beer commercials? I had five Spuds MacKenzies on a flight from New York to Los Angeles. Each dog had its own seat in business class.

Animals are quiet, they never complain about the food. They don't pull on my dress or yell at me when we run out of space for their bag. I'll take animals over people any day.

But there's a limit.

A limit with storage space. A limit to how many passengers can squeeze into an airplane. (Although the airline doesn't seem to recognize that one, does it?) And animals are beginning to make my job difficult.

A couple weeks ago, a passenger made headlines when she was kicked off a plane with her "emotional support" pig. A full-grown pig. On a plane.

Seems the pig caused a disruption, pooping right there in the aisle. The airline had allowed the passenger to board with it because it was an emotional support animal — and yes, a full-grown pig qualifies as an emotional support animal.

So does a miniature horse.

I can barely get 14 first-class coats to fit inside the closet on a Boeing 737. I have yet to run into a bulkhead row big enough to accommodate a horse.

Airlines really do try to do everything they can to accommodate service and emotional support animals. They have to: It's the law. Not once have I seen an animal of any sort turned away.

From my airline's policy on service animals:

A service animal may accompany a customer with a disability in the aircraft cabin, provided the animal can be accommodated without obstructing an aisle or other area used for emergency evacuations. If a service animal is disruptive or too large to fit under the seat or at the passenger's feet without encroaching on another passenger's space or protruding into the aisle, it will need to travel in a kennel (provided by the passenger) in the cargo hold. There is no charge for service animals used by customers with disabilities. However, credible verbal assurance that the animal is providing a service to assist with a disability will suffice should an inquiry be made.

Now, I'm the last person to judge anyone's mental state. I'm all for emotional support animals on board for passengers who suffer from anxiety and other mental health issues. However. I'll be the first person to tell you I don't want livestock on my flight. Not when there are 150 other passengers on board.

The problem is when passengers abuse the system to avoid the airline's pet fee and keep their pets on the plane or in their laps. Over the last two or three years I've noticed a lot more emotional support animals on board than ever before. New York-to-Los Angeles seems to be the most popular route.

At my airline, a passenger must pay $125 to bring a pet onboard, and only seven pets are allowed on any one flight. If the pet doesn't fit in a carrier under the seat — where they are required to stay — it has to travel in cargo, which costs $175.

This is things that have gone to far: A rooster on a plane, in a pink tutu, as an "emotional support" animal. pic.twitter.com/PLpuf4EH5Z — Sue Strachan (@SueStrachan504) September 15, 2014

I can't tell you how many times I've walked down the aisle and spotted a cat or dog lying on a passenger's lap. I have to remind the passengers to put their pets back inside the carriers, at which point some of them will inform me it's an emotional support animal. Here's the thing: Before takeoff I get all kinds of information about the flight. I know exactly who's on board, including the number of pets and service animals. If the animal is not listed as a service animal, it's considered a pet and has to stay in its carrier. While I'd love nothing more than a plane full of cute and cuddly cats and dogs, not everyone feels the same way. Like, say, the passenger who got bit by a dog after it escaped from its carrier.

In training, we're taught how to evacuate a plane in 90 seconds, how to take down terrorists with our bare hands, how to put out fires and — of course — how to serve a five-course meal. But there was nothing about animal control.

These days it's hard making everyone happy. Flights are full, and it doesn't help that many airlines have removed closets and even made lavatories smaller in order to squeeze more passengers on board.

It's gotten so bad, there's not even enough space to bend over and reach into your bag without smushing your face against the seat in front of you. When I'm rolling down the aisle with the cart and look around, I feel your pain. I really do. And I do what I can to make people happy with the tools I've been provided, but it's impossible to please everyone.

On one flight, a man who looked like he could have been a professional boxer kept his emotional support kitten in his lap the entire flight. It melted my heart.

The lady sitting next to him never said a thing, just stood in the aisle the whole flight. It wasn't until the seat belt sign turned on and I asked her to take a seat that I learned she was allergic to cats. She refused to sit down. There weren't any open seats to move her to.

This is what I have to deal with, and it's fine because it's my job.

But a pig? Really? If I can't find a passenger willing to sit next to a kitten, how am I supposed to find one who won't mind sharing a row with a barnyard animal? Just thinking about it makes me want an emotional support drink. Flying can feel like an episode of Survivor. Trust me, I know. Which is why I think we should all do our part to make things go a little smoother. Like adopting a more conventional animal than a pig or a peacock. How about a cocker spaniel? Or a guinea pig?

FOR REAL: flight attendant discussing how man on earlier flight had a peacock with him as an emotional support therapy animal. — Susan Orlean (@susanorlean) August 29, 2013

Heather Poole is a flight attendant for a major U.S. carrier, and the author of the New York Times bestseller "Cruising Attitude: Tales of Crashpads, Crew Drama and Crazy Passengers at 35,000 Feet." You can follow her on Twitter at @Heather_Poole.

Have emotional support animals gone too far? Share your thoughts in the comments.