I kinda take advantage of mine too. My supervisor is never here. And his office is about 1/4 mile away from mine. So it's not like he checks up on me (when he actually shows up for work). So I pretty much just come & go as I please. My students don't care if I send them home 2 hours early. If he calls, and I'm not here, I can just say I was in the bathroom & didn't check my voicemail when I came back. But I just bored out of my rabid ass mind.