Hyuuga Tenten
Tenten was in love with Neji. So in love that in fact, she wrote Hyuuga Tenten all over her Notebook. They had the hearts and everything that a girly girl would do. Tenten didn't know why she did it. She just loved him too much.
One day, Neji asked Tenten,
"Can I borrow your Notebook?"
"Sure." Tenten said totally oblivious of the fact that Hyuuga Tenten was written all over it with hearts.
Tenten was working on another assignment when she realized that she had written Hyuuga Tenten all over it. She turned around and shouted,
"Neji!" Neji turned around and said,
"Tenten, I know you like Hinata and want to be her older sister and all… but this is a little overboard."
Tenten stood there for a second. Neji, the genius Neji, didn't know that Hyugga Tenten meant her future name if she married Neji. Instead, he thought that Tenten wanted to be Hinata's older sister, which would also equal Hyuuga Tenten but…
"…What?" Tenten said staring at Neji.
This is proof that even the smartest people can be totally oblivious when it comes to love.