Donna proposing to Gaz, after previously rejecting all of his proposals. He accepts.
Pretty much any time that Donna and Janet hug.
The ending of season eight, when Gaz chooses Donna. Doubles as a Tear Jerker.
It's always been you.
During season seven, Louise considers getting an abortion due to her own petty reasons for not wanting a girl, and it seems like she doesn't care about her unborn child at all. However, when the baby's heartbeat doesn't show during a scan, she realises that she does care and is genuinely freaked out, desperately pleading for her child to be okay.