It's the inability for guy #1 to confirm a date with gal #1 because guy #1 is waiting on gal #2 to confirm. But gal #2 can't confirm because she's waiting on guy #2. But guy #2 can't confirm because he's waiting on gal #1. So no one can confirm the date because they are in dating gridlock.
I sent a tentative invite to Michelle for dinner on Thursday night but I couldn't confirm because I was waiting on Jennifer to let me know if we were a go for Thursday. It turned out Jennifer couldn't confirm for me either because she was waiting on Mark to confirm their plans for Thursday night. Who would have guessed that Mark couldn't confirm plans with Jennifer because he was waiting for Michelle to confirm?? Thursday came and went and none of us went on a date because we were all stuck in "dating gridlock"