Power
You do get to boss people around all day. But the people you're bossing around are mostly thieves, drug-dealers, rapists, and murderers, and they're not likely going to make you feel particularly…powerful. Do you really even care if these people like or respect you?
However, you also get to walk around all day in uniform with a weapon at your side. So while you may be surrounded by individuals who are doing their best to intimidate you, it's hard not to feel like a bit of a big shot. We still wouldn't recommend that you "na-na-na-boo-boo" any of the inmates through the bars of their cells, though.