Open for suggestions!
Get some halloween contacts.
Step 1) Show up, be all sweet and bubbly and happy and shit.
Step 2) Before bringing their order to them, put the contacts in, and act totally different. Quiet. Smirking cruelly. Lower your voice as much as possible without sounding funny.
Step 3) DON'T laugh.
After your required communications with them, shoot them a quick, subtle, suspicious look as though you know their secrets.
Turn them into schmuckers.
If you are wearing jeans put red food dye in your crotch. Scratch often.