Man... even Star Trek had Raktajinos. Your fandom fails.
Okay, so, coffee is a drink that's very high in caffeine and a lot of people drink/drank it on a regular basis. Like, seriously. Ask anyone here.
It's a stimulant. It makes people more alert so, naturally, every one started drinking this stuff in the morning. Fast forward a bit and a bunch of corporations decided to make it their primary source of revenue. Legalized drugs on every street corner. Coffee Shops + Caffeine Addicts = $Bank$