[wikfwikf]

How did you know the person was addicted to crack?

[klabb3]

Guess who sold him the crack.

[bittercynic]

Not the person you're replying to, but...

Of course there are other reasons they might act that way, but "crack addict" is a sometimes just shorthand for a person who's acting and looking a certain way.

[Integrape]

Could've been a jenkem connoisseur, but still apparently having a bad day.