Picking on Students

My personal belief has always been that a teacher should not pick on students directly. Joking around is one thing, but giving students a hard time by picking on or making fun of them is completely wrong. I feel that picking on students can lead to them no longer wanting to be in that class. Students have it tough enough being students and teenagers with the peer pressure and other issues they go through. Why would a teacher want to add more pressure to these students in the classroom by picking on them. This puts the students on the defensive rather than feeling comfortable in the classroom. It frustrates me when I see teachers doing this. Teachers are there to make the classroom and the entire school a positive learning environment where students feel comfortable sharing their opinions  and being who they are. 

I saw this happen in a college classroom today. A teacher spent a good amount of the class giving a student a hard time. I found this to be a waste of valuable class time as well as insulting and demeaning to that student. At any educational level this is inappropriate. Sorry if this seems like a rant, but it is something that made me really angry because it wasted so much time and was so insulting.