Spit balls

I don't understand why guys will spit while walking. Ew. My best friend and I were talking about this subject last week, when she was complaining about this topic,and of course a few days ago it happens to me. I was strolling along to fourth period when suddenly this guy, who's with his friends, starts to prepare his giant, disgusting spitball. Luckily, I saw it hit the ground and I moved out of its path before I got giant, disgusting spitball on my shoe. The producer of the nasty specimen saw my look of disgust and laughed with his friends. How mature. But in the past couple days I've noticed more and more guys spitting. I mean, is it necessary? Do you actually have a loogie (although that makes it even more nasty)? All the times I'v dodged peoples' spit, other people step right in it. That's how it is, right? Grody:P