Inside: Reason 3. Because the word congratulations is so long that people hate writing it out themselves + they'd much rather just buy a card that spells it out for them.

Got your panties in a bunch?

Front: You only get married once. Back: Theoretically.

Front: It's Valentine's Day again. Inside: Let's get drunk.

Front: I love you so much. Inside: You're so fucking hot.

Front: Hello. Back: Whore.

Front: Sending Christmas cards is almost a lost art. Inside: So you're an asshole if you don't return one.