If a teacher can get along with the majority if not all the students, then classes would be so easier, but unfortunately there are those asses of students that just wanna piss off their teachers. Why they want to do this is beyond my understanding. What I fucking hate the most is when they get caught doing something they shouldn't (aka phones out during class) they just quickly try to cover it up and if the teacher actually takes it than just a "put it away, this is your last warning blah blah" then the student acts as if the teacher hates him/her. Sometimes I just wanna smack the students who do this, maybe I just don't understand the whole phone thing since my phone is, compared with pretty much everyone else's phone, shit. This is also why I kinda don't want those kinds of phones, they might do the same to me, but since I'm pretty much antisocial irl I'd like to think I wouldn't become like them.
I have had teachers who actually are very strict, so no bullshit gets pass them, but at the same time class is dull and like a prison (aka my 7th grade language arts class). Actually right now I have two teachers who do yell, but just to make things clear but without the rage. One is my Studio Arts teacher who is known for being "crazy", I see why they think that and I agree, but I love that class, not only for drawing but the teacher is a pretty cool guy, when he's not angry (which only happened for like 1 day). The other is my stats teacher but even though its a boring subject most of the time he makes things fun or at least attempts to while we actually learn about stats.
All in all I personally feel as if the students are more to blame, but some fault can be blamed to the teachers.