Eh... Honestly it seems a little... basic to have coffee. I think peoples priorities for drinking things are booze in a post apocalyptic world.
I would suggest smoking, since cigarettes were everywhere in FO3, to temporarily add to your endurance and stamina (helping you relax) with serious withdrawal effects of negative charisma and endurance and health.
However, there's that whole "No smoking in video games! Oh my god they are corrupting our children" even though its in a game with and not limited to:
Alcohol
Drugs
sixual references
Violence
Torture
Gambling
Prostitution
Murder of innocent people
Theft
Slavery
the list goes on.
Anyway, my point being, Cigarettes might not be a horrid idea, after all, it would make sense for people to be smoking them, especially since you saw people in FO3 smoking them.