I worked as a flight attendant for 2 years. Here are 10 things you should never do on a flight.

• I was a $4, and I really wish passengers would stop doing certain things.
• It's pretty gross to go to the bathroom without shoes on or leave the toilet unflushed.

I worked as a $4 on domestic and international routes for two years, and I saw all kinds of behavior on planes.

Read on for the top things you should never do on a flight.

The life vests under the seats aren't yours to steal

I never thought this would be a problem, but some people think a life vest would be a nice souvenir.

Not only is it stealing, but you could also be putting the next passenger sitting in that seat in danger.

Do not leave the toilet unflushed

If you don't know exactly how to use the airplane bathroom, don't be shy or embarrassed to ask your flight attendants.

You don't fly the plane every day, and there are so many buttons. But don't just leave and hope no one will notice.

$4 is a very small space. We usually have one bathroom in the front and two in the back, so everyone can tell when you didn't flush.

It might be best not to take medication that makes you sleep through the flight

When I started flying in 2019, I noticed a passenger looked unconscious to me. I tried to wake him up by shaking him, but he didn't respond, so I panicked and called my colleagues for help.

I was about to ask for a medical professional onboard or perform first aid. But it turned out a passenger was a heavy sleeper, and it looked like he'd used some sleeping medication.

You might not want to scare your crew by taking drowsy medication on a flight.

Bringing too much luggage on the plane makes everyone's life harder

$4 are completely covered with sweat from carrying too many personal items, backpacks, and carry-ons.

It's so much easier to check your luggage and walk on the plane relaxed and stress-free.

It's also not always possible to find a space for everyone's bag, so your extra items may need to be checked regardless. If you're worried about paying extra, ask an attendant at the gate. They're usually happy to check it for free if the flight is full.

Never drink any personal alcohol onboard

We catch people drinking mini bottles of alcohol all the time.

Even if you think there isn't a flight attendant around, you'd be surprised how often other passengers let us know.

It's prohibited, and you could be banned from future flights with the airline if you're caught, so it's not worth the risk.

Crew members can't help you place your carry-on into the overhead bins

Sometimes passengers ask flight attendants for help hoisting their $4 into the overhead bins. But that isn't part of a cabin crew's responsibility.

If the bag is too heavy, it's better to check it.

Don't go to the restroom when the flight attendants are performing a safety demonstration

It's OK to go to the restroom before takeoff. But when you see flight attendants performing a safety demonstration, you should stay seated and wait until the seatbelt sign is off.

When passengers get up during the safety demonstration, we need to stop, wait, and start from the beginning when everyone is back to their seats.

If it's an emergency, call a flight attendant over and we'll help you.

Always wipe the seat-back trays before using them

You may think that people only place drinks on seat-back trays, but the person before you could've slept on it or used it to change a baby's diaper.

My airline hands out little alcohol wipes during boarding for a reason. Just give the tray a quick wipe when you sit down.

Never go to the restroom without shoes

The bathroom is probably the dirtiest place $4. And all the liquid you see on the floor isn't just water.

Plus, if you're just wearing socks, they'll be soaked. Who wants that for a whole flight?

Don't stay silent if you aren't feeling well

I've had $4 feeling lightheaded or having a panic attack, but they were too shy to tell anyone.

You don't have to quietly deal with pain or discomfort on your own until landing. Always tell your flight attendant. We might have the training or equipment that can help.