I'm freaked out because I had to wear  a seatbelt in a cab
Why did you freak out about the seat belt?
Because I don't wear one in cars.  They're stupid and uncomfortable
Even though you do not like to wear a seat belt because they are uncomfortable you should still wear one. Thus people are expected to buckle up in a cab.
I'm not going to wear the seatbelt since it's dumb and uncomfortable. I don't get why people are so paranoid about those things.
It may seem dumb, but car accidents are much more common than most people realize, especially in city driving.  The cab driver will insist that you wear a seat belt, because, if you don't, he could be held liable for any injury in a crash.  Even though it's uncomfortable, you should do it for your own safety and for other people.