So this is a question I think about and tonight an episode aired and im likely practically for sure its my favorite scene of any trek. Granted most of my favorite trek scenes involve spock.
EDITED - so glad I made this post. Its cool to see or hear about peoples scenes.
ST:TNG - Data’s daughter, Lal, is learning about human relationships by observing people on 10 forward. Her reaction when she sees two people kissing always tickles me. “He’s biting her!”