I love being a thief. You have so many fun ways to mess with people and tons of ways to do good RP with it.
It's a common sentiment that people don't like it because of the fact most of your objectives can be completed easily, silently, stealthily, and fast, and after that your a glorified pacifist until shift end.
A) Thief has a ton of fun and creative combos you can do that lead to unique ways to accomplish your objective.
B) Thief CAN be played silently, but you can also play it very loudly. Some of my funnest moments as thief is when I rile sec up so much I have the ENTIRITY of sec chasing me through space and still fully greentext.
C) With your ability to steal ID's of anyone and with tons of ways to break into places you basically have AA.
Anyways these are the reasons I like thief but mainly because I'm an utter gremlin that LOVES harmlessly resisting arrest.