This is the most famous "thing" in literature. Little Marcel sits down to tea with his mother and takes a small bite of tea soaked madeleine....
"but at the very instant when the mouthful of tea mixed with the cake crumbs touched my palate, I quivered, attentive to the extraordinary thing that was happening inside of me."
Then he tries to hold onto this fleeting memory. This powerful, joyful thing.
I wish I had not known about the madeleine. I wish I could have tasted it for myself.