Spitting is fine.... But when people spit in areas of decent foot traffic, it's annoying. On the sidewalk, on the stairs, in the parking lot, on the restroom floor, etc. Doesn't matter if it's just saliva, seed shells, chewing tobacco. It's absolutely annoying when you find yourself accidentally stepping in someone's spit or having to dodge a minefield of spit on the ground.
Working at a dealership, somehow almost all the salesmen eat sunflower seeds and spit the shells all over the customer parking area or even the restroom floors. Heck, I even see them still eating them and spitting mid conversation with a customer or co-worker. It's just plain gross.