Hilarious e-cards are great, but what if you're an old-fashioned person who likes delivering snarky, possibly relationship-destroying sentiments via the postal office? Or even just by handing out said sentiments in a bar? Then head to ATown Boutique to pick up greeting cards from Trick Pony Studio.
Tiny enough (1.75x2in) to store in your wallet, Pony's cards take care of business via pictures of dogs taking poops, unicorns shooting rainbows out of their butts, and Bat Signals edited to include a pair of boobs, which is how you really make the Dark Knight rise. Half the interiors are left blank to be filled with your own broetry, while the others sport wondrous punchlines, e.g. "You Stink" ("'Cuz you're the s**t!"), "The word of the day is Legs" ("Spread it!"), and "If I gave you money you'd just blow it" ("That's why I stuffed $100 down my pants").
ATown's also carrying Pony shirts "that make your third nipple virtually invisible", though if you're really set on destroying a relationship, take that shirt off!