Deidara. He lost to the Uchiha so much he was on the verge of tears in front of Sasuke.
Sakura. Always punching Naruto like a retard but failing to realize that she is less useful than Part 1 Naruto. Always gets upset and goes and cries in a corner.
Obito- You let Rin die. He looked pretty rustled there.
@OP sorry I mentioned couple, just had to point it out there, though you were asking for only one.