He annoyed me so I gave him espresso instead of decaf.
What would you give him espresso instead of decaf?
A while back he gave me caffeine instead of decaf once.
That's a really rude things to do. It can be harmful to give people the wrong type of coffee, because they might have trouble with all that caffeine.
I thought it was only fair payback.
It can be really dangerous for people with heart conditions to ingest too much caffeine. If something happens you could be charged for knowingly tampering with food. It is really serious dude!