You'll stay up later
But not as late as most people think. Despite the popular myth, drinking a cup of coffee in the afternoon won't turn you into an insomniac. Caffeine is obviously a stimulant, but the caffeine you consume in your post-lunch cup is processed through the liver at lightning speed and roughly 75% of it is flushed out of your body within four to seven hours. So, if you go on a coffee date at 8, you'll be able to call bullshit on your date when they say they're getting sleepy at 9.
You'll talk about something actually important
Coffee makes you smarter -- not, like, superhuman smart -- but smarter than a depressant like alcohol. This might be hard to grasp, but take a sip of espresso and try to follow along. Caffeine blocks the effects of an inhibitory neurotransmitter called adenosine. Adenosine is a neuromodulator that is believed to play a role in promoting sleep and suppressing arousal. The suppressing of adenosine, combined with the stimulating role of caffeine, increases neuronal firing in the brain, releasing neurotransmitters like dopamine and norepinephrine.