Sometimes, if you've gone through a long intellectual drought, you experience a sudden shock to the system when you encounter someone of even modest intelligence. Often, this tends to make me act incredibly stupid as I try to re-adjust.

It's kind of like when you jump head first into a pool of really cold water. You reach the surface and gasp in air as your body freaks out. This will cause the intelligent person to eye you warily as they try to edge out of the conversation and find someone a bit more normal to chat with.