There is a special ring in hell reserved for people who are rude to others in the service industry. And yet, some people seem predisposed to it.
To those people, I say: Look, just because you are sitting at a table and someone is bringing you food and wine doesn't mean you are actually a despotic emperor whose subjects are bound by vows to fulfill all of your brutal whims.
Now, I'm not sure what constitutes 25 cents worth of smartass (keeping your headphones in? Snapping to get the waiters attention? Fork-slaughtering a squirrel?), but I love how reasonable a charge it is. Whomever this "clerk" is, he or she is not trying to punish this guy financially, he or she just wants him to know he's a douche.
Also, wait a second, what is this place? It only sells miscellaneous goods. Either this is the laziest cashier/waiter/clerk ever or this is a receipt at a sex shop that cares about the anonymity of its clientele.