Veterans.

1) Overcharging students
2) Putting subliminal messages in endcap signs
3) That obnoxious buyback woman who sighs, and whines about everything, and demands to speak to someone about how outrageous it is that we aren't giving her more money, and just has a thoroughly unpleasant attitude- every single semester
4) The poltergeist in the Architecture section that always messes up the books there no matter how often you straighten
5) Destroying books and magazines in front of customers
6) ActiveDirectory
7) Finding invoices
8) Plotting to annex GM, enslave their workers, pillage their merchandise
9) Nibbling on candy, then putting it back so no one notices
10) Slack-off-Sundays
11) Getting M[] in trouble