That awkward moment when you’ve said “What?” three times, so you just say “Oh, yeah..” even though you have no idea what they said.

Commentary:
Ah, the classic "What? What? What? Oh, yeah…" maneuver – the universal signal for "I have no clue what you're talking about, but I'm just going to nod and smile anyway." It's the verbal equivalent of doing a little dance to distract from the fact that you're totally lost in the conversation.