So many.
S.1 E3 w/ Felicity - 'I didn't study Shakespear at any of the four colleges I dropped out of' - there's that adorable puzzled eye roll he does where he's confused but also doesn't want to be caught out
S1 E12 w/ Felicity - 'I ran out of sports bottles'.
S3E5 w/ Donna Smoak - Where he mouths Mom and is grinning and trying not to laugh.
S.4E7 or 6 where Ray is all excited and Oliver just shoots him a look like, this is not funny!
Nearly every second scene with Barry.
S4E8 - 'I spent 5 years on an island in the north china sea Barry, i don't get cold'.