This. I took Calc 1 twice. First time was during the day in a big auditorium style classroom. The prof had a pompous attitude, like he didn't even want to be there. I dropped the class mid-term. I re-took it in the evening. Smaller class size, mostly "non-traditional" students. Prof was awesome. Frequently stopped the lesson to re-explain things and made sure everyone was understanding, stayed after class to help students. Because of that class I actually "got" calculus.

Yes, and I believe many colleges make it intentionally difficult. My Calc I class was given by an instructor with a heavy Asian accent. I had to struggle to understand every other word.

My Chemistry for Engineers class was in a large classroom that was under construction.

Needless to say, I went for MIS instead of CS/EE. I ended up taking many CS classes, so it worked out well.

On a side note, teaching is really difficult. Knowledge of the subject is the minor skill. My parents were teachers and I considered it in college but didn't have the patience.