Flying is fun, but there are definitely ways to make the experience less enjoyable for you and for those around you.

If you’ve flown often, you should hopefully know the standard operating procedures for how to be a good passenger.

It doesn’t matter if you’re in business class or at the back of the airplane. It doesn’t matter if you’re on your seventh plane of the week or if you’re on the first flight you’ve ever taken. Don’t let anyone tell you otherwise.

Here are some of the things you should never do on an airplane:

Do not eat anything that touches tray table It’s been shown that there are more bacteria on your seat-back tray table than in an airplane’s bathroom. Think about how many times a plane is turned around and whose hands, napkins, tissues—and worse—have been on that table.

Do not Get Drunk not only is it socially unacceptable to make a fool out of yourself—running the risk of causing an incident that could require crew intervention or, worse, an emergency landing—but you’re going to need your wits about you for even the simplest task of getting to your next gate.

Do not be silent when you feeling Sick Flight attendants are well trained and they know how to assist you, so if you’re feeling sick or queasy, don’t keep it to yourself. Let a flight attendant know. They are trained to deal with every imaginable scenario, and an ill passenger is one of them.

Do not wear a contact lenses Contacts usually make your eyes drier. Combined with the dry air inside the plane, this brings rather uncomfortable results. That’s why you’d better wear glasses or one-day lenses if you have a long flight. You will also need eye drops.

Do not take rare seat if you have motion sickness This is especially true on a long-haul flight. For starters, your space is limited as it is, but you also run the risk of getting a blood clot sitting for four, five, six hours or longer. Get up (not during the meal service, of course) and walk the aisle.

Do Not take your shoes off There are few things as nauseating as someone’s sweaty feet unsheathed from raggedy sneakers. You might be more comfortable with your shoes off, but please spare the rest of us on the plane. If you really need to kick your shoes off, please replace them with a pair of slippers or comfier footwear so your fellow passengers can breathe.

Do not touch any object for no reason  Former passengers could leave anything in the seat-back pockets and on the tray tables. Sanitation does not take place after every single flight, so all the bacteria can migrate to your hands. Don’t touch anything excessively, and take alcohol wipes with you.