Watch Zoku Sayonara Zetsubou Sensei

This show is the story about a young man named Nozomu Itoshiki, who also goes by the alias, Zetsubo-sensei. Nozumu is not only a school teacher, but he's also the most negative and pessimistic person on the planet. He teaches his class that life is a huge disappointment and offers nothing but agony and despair. However, his students aren't the most normal children in the bunch. Some of them of quite weirder than others, including a girl who is not only extremely positive about life but has a huge crush on Nozomu, a stalker, an overly perfectionist class president and even a foreign exchange student who has split personalities.