Dumbfounded jokes

A guy took his blonde girlfriend to the Super Bowl game.

They had great seats right behind their team's bench.

After the game, the guy asked his girlfriend how she liked the experience.

"Oh, I really liked it!" she replied, "Especially the tight pants and all the big muscles, but I couldn’t understand why they were killing each other over 25 cents."

Dumbfounded, her boyfriend asked, "What do you mean?"

She said, "Well, they flipped a coin, one team got it and then for the rest of the game, all they kept screaming was, 'Get the quarter back! Get the quarter back!' I’m like, hellooooo! It’s only 25 cents!"

A man awakes in a hospital and is confused. He decides to feel his legs, but to no avail.

"Doctor, doctor!" He cries out.

"What is it?" The doctor asks.

"I can't feel my legs!"

The doctor stands there for a moment - completely dumbfounded.

". . . That's because I amputated your arms."

English is weird. It can be understood through tough, thorough thought, though.

Me: Do you ever just walk into a room and forget what you were doing?

Bank teller: [eyes wide] Uhhhhh...

Me: *scratches head with gun* Man, I hate it when this happens.

I’m trying to find out what IDK means. Every time I ask someone, they say, "I don’t know."

How do our brains remember that we forgot something, but we can't remember what that thing was?

What the heck did I discover?