a) you get paid weekly
b) your time doesn't get monitored, so you can turn up at 8:40am (just before everyone else), tell your colleagues you've been here since 8am, take your full hour lunch, leave at 4pm and get paid for the full lot.
c) in addition to the company not monitoring time, you can rape the OT double- (or triple-)pay period and nobody knows any better
d) you depart your position in a comparatively short time period, so any horrific mess you make (be it invoices or examination results, to ad lib a couple) is of no concern to you
e) you can always use the excuse "i didn't know what i was doing" because you don't get properly trained
f) seeing your name on internal envelopes makes you feel more important than you are