Anyone who has had the pleasure of a commute on public transportation will probably tell you that it is a bit of a double-edged sword. When it’s great, it’s great-a pretty inexpensive way to get to work on time, maybe while reading a book and enjoying a cup of coffee.

But when it’s bad, it’s so, so bad-an infuriating, hot, crowded mess of a disaster that fills you with a rage so hot that you honestly think that you could pick up one of the train cars and hurl it back to whence it came.

There are a few unspoken rules that commuters are expected to follow in an attempt to make this potentially horrific experience a little less painful for everyone involved. There are the obvious ones like ‘give up your seat if someone appears to need it more,’ or ‘don’t put your bag on a seat to save it, even if you think that your bag deserves a seat more than the person standing in front of you, you jerk.’ But recent experiences indicate that there is some confusion about what is and what is not acceptable when riding public transportation, so a few basics have been outlined below. Feel free to view it as a user’s guide for commuting with others.

1. While on public transportation, do your best to keep grooming and other forms of personal hygiene to a minimum.
This includes, but is not limited to, the following: brushing your hair, putting on makeup, applying deodorant, clipping your nails, flossing your teeth, or any form of shaving. I know what you’re thinking: “Why, that goes without saying! Surely no one would ever do that on public transportation!” Alas, you are mistaken, for all of these examples made the list for a reason, and that reason is that I, a member of my immediate family, or a close friend have witnessed them firsthand. In fact, just this morning I was sitting next to a woman who was applying makeup so furiously that the gentleman next to her got off the train with rouge on his cheeks. Look, we’ve all been there-you sleep through your alarm, you don’t have time to apply your face before you rush out the door to catch the late bus. What a way to start your day! But want to know an even worse way to start your day? A stain on your skirt from the dummy next to you dropping her bronzer brush. Do everyone else a favor and find a bathroom or alley in which you can wrap up your morning routine.

2. If something is making you angry enough that you feel that your only course of action is to yell at somebody, just do yourself a favor and get off at the next stop and wait for another train.
No matter how noble your cause, no matter how chivalrous your intentions, you will look like a loon if you start yelling. I’m not saying you should sit idly by while injustice reigns supreme, I’m just saying that often times folks battle said injustice in a way that leaves everyone else edging nervously away rather than cheering them for their stance. No one in the history of public transportation has looked sane walking away from a situation in which they screamed at someone. It won’t help, I promise.  If you really feel the need to hurl your two cents at strangers, do so calmly and rationally, it will get you a lot further. And as a rule, unless you’re at a concert, rally, or sporting event, try not to scream in public. It’s jarring and it makes everyone else nervous.

3. Unless you’re a diabetic and your blood sugar is rocky, don’t eat while on public transportation.
The other possible exception would be some sort of Amtrak train ride on which food is served because the ride is so long. If you’re on the train for the duration of an average commute, you can wait until you’re off to eat. If your day is so busy that the only possible time to squeeze in a meal is on a crowded train, then you need to reevaluate your schedule. And also, you probably look like a Muppet when you eat, and not one of the cute ones. Crumbs everywhere and upper and lower lips never making contact. Possible allergies of the other passengers aside, eating while on public transportation is just gross. Do you even know how many germs are screaming around the average train car?! No? Well me neither. But my guess would be “zillions.” And while we’re on the topic, take it easy on the gum. It never did anything to you.

4. While on public transportation, refrain from playing your music sans headphones.
It is so sweet of you to want to share your music with the rest of us. Really, SO sweet. But (and don’t take this the wrong way) it isn’t guaranteed that everyone will share your taste in music. Maybe that 4-year old in the next row was listening to heavy metal or rap riddled with curse words while she was packing up her Dora backpack this morning and now she feels like switching up her genres (I know, so rude). Who knows? Either way, we can see the headphones in your pocket. Do us all a solid and toss ’em in the old ear holes. Singing out loud also falls into this category. While we’re all super proud of you for nailing that high note in “Poker Face,” sometimes it’s nice to be able to, you know, not hear you singing. The only exception would be for those who have stupid good voices and start out singing quietly and then someone hears you and asks you to sing louder and you sheepishly decline but then everyone keeps encouraging you so you reluctantly get up and crush some Queen or Abba. Like, seriously dominate it. But usually its not the gifted singers who give it their all on the train, so shut it down.

I hope this guide proves useful for you and that you enjoy your next public transportation experience! But remember to behave yourself. We’re commuters, not animals.