Does Underground Subway Have Wheels Spitting On The Sidewalk/in Public. Is It Really Necessary?

Spitting on the sidewalk/in public. Is it really necessary? - does underground subway have wheels

I moved into a great city and I have never seen, both public and spitting. It disgusts me and if that happens, I must fight the urge to say something. Obviously this is acceptable. You can not even walk 1 block without relying on someone to spit. I am often tempted strange things, but somehow I feel to be reasonable when it comes to that.
He reached the height of the other day as I waited for the train at a subway station. I had my bag sitting on the floor (next to me have to wait too heavy). The train stops and a man well dressed down. The first thing is a huge ham loog on concrete, about a foot out of the bag of food. I gave him a disgusted look and mouth seriously "?"Followed by a sigh of annoyance. Adults do not feel comfortable reprimanding others, but I think it's because I've never had, It dass a windy city and is asking people walking in front of a small skewer without moving when we hit the person behind.
I understand that if a bug flew into his mouth, you play a sport in a meadow or the taste of saliva in the mouth suddenly change back ...... but in the streets, entertainment stages, stairs, subway stations? Why do this? I estimate that about 1 out of a spit of 50 people in this area. Can you imagine if everyone did that? Our shoes slipped on the subject, let you fall and then. I'm sure you accidentally touch or move to obtain, they spit all the time. Why?