In my time at the store, I've done the following things:

Faked enthusiasm/a love for someone's purchase of:

Sudoku (many times)
You: the Owner's Manual (many times)
Natural Cures They Don't Want You To Know (many times)
Japanese films
Silent films
Japanese Silent Films (I guess my film studies minor is paying off for being able to discuss obscure movies with people)
The Snowman
Pern (multiple times)
Cookbooks
Nuns Having Fun calendar
Pig calendar
Eldest (many times)
Eredragon (many times)
Harry Potter (many times)
Lemony Snicket (multiple times)
Microsoft Access for Dummies
Foreign Language tools (many times)
Frank Sinatra
Dean Martin
The Kingston Trio
Joni Mitchell
He's Just Not Into You
Boris Vallejo (*shudders*)
The Ramones
Guns, Germs, & Steel
Dune


Actually Been Enthusiastic About Someone's Purchase of:

Kurt Vonnegut
Ben Folds
Time Traveler's Daughter
Kevin Smith movies
Death Cab for Cutie
System of a Down
Audioslave
Foo Fighters
Lifehouse
Roald Dahl (multiple times)
Orson Scott Card
Napoleon Dynamite
CCR
The Little Princess
The Secret Garden
Chronicles of Narnia
Arthur C. Clarke

Pretended not to be Judging Someone for Their Purchase (while secretly judging them inside) of:

porno mags
Boris Vallejo

So now you know what your cashier is probably really thinking the next time they banter with you about your purchases. Except, if you're buying something awesome. Then they're genuine about it.

But actually, I really do like my job. Of all the jobs I've ever had, this is the one I complain least about on a day to day basis. And also, I value interaction with people, even when I AM being a complete phony. So there's that.