What is the most annoying chess opening u ever played against?

Budapest gambit: I decline gambits on policy and have no idea how you safely decline this one

the closed sicilian

I believe all sicilians should be opened up

to close it, it's cowardly, but that's just my opinion

That would probably be the Caro Kann. Probably because I skimped on studying it properly.

Four knights game - it's so boring!