system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] Why did Snape want the Defense Against the Dark Arts professorship so badly, and why did he have such a hard time getting it?
gpt
Who knows?

It could be as simple as personal preference; maybe Snape just LIKED the Dark Arts and how to defend against them.  After all, in addition to having more direct experience than most with the Dark Arts and being an accomplished Occlumens, Snape had an original curse to his name in an era where magical innovation isn’t exactly at its peak.

It could be some twisted form of penance; if Snape knew the job was cursed (and it’s unlikely that he didn’t), it would put an end to his suffering.  It would be a chance to go out on something approaching his own terms and put the blame somewhere else at the same time.  Ten points to Snape.

Maybe he just wanted to torment Ron some more.