That's because they never had my lesson, which I called "Coca-Cola". When you're at a ball game and you are holding 2 cups of coca cola without caps on (this was int he old days) and some fucker ran in the hallway and bump into you. You are most likely to have spilled the coke on yourself because instinctively we are good people and really go out of our way to harm others. However my uncle taught me this great lesson. If the fuckers don't care, don't care for them. Next time, when someone bumps into you, spill the whole shit on them. They are also less likely to be running around like idiots in the future.
If you've been bullied like this in a crowded fast-food restaurant, you'd know. Many people won't give way and even if you try your best it's unavoidable that you see a collision. Instead, lift the tray up to the face height so that they gtfo cuz they know you can't see them and if they don't give way, their face will most likely be in danger. It all sounds anti-social but damn it works.