What was the sweetest scene in the entire series for you?

Depends on what 你 mean 由 sweetest? Do 你 mean like touching.
Gosh there are so many.......<3

But anything that has to do with Itachi, the guy is a Legend.

火影忍者 meeting hid dad.
...and then just punching him in the stomach :D

But actually that was a very heartwarming reunion. Finally 火影忍者 found out that there's a reason behind everything that has happened.