Keep in mind, I am choosing only 6 episodes in individual seasons.
Season 1: Boast Busters-Spike would not confront Snips and Snails, the Mane 6 would shun Twilight for not standing up for them, prompting her to reproach Trixie to defend her friends's honor at last.
Seaon 2: A Friend in Deed-Pinkie Pie would board herself up in her room in fear of bothering anypony else instead of massively apologizing to Cranky, prompting Cranky to realize that he went too far with wanting solitude.
Season 3: One Bad Apple-The CMC would run away from Ponyville, but AJ saw them leaving while seeing the harvest festival and stopped them, forcing the CMC to finally admit Babs' bullying, prompting Babs to get a comeuppance and a change of attitude.
Season 4: Trade Ya!-After the ponies learn their lessons in the episode, the trade vendors would reward them by giving the stuff they wanted for free, AJ would get the pen, Rarity would get her second brouche, Fluttersh ywould get the bird whistle, Pinkie would get squat as she wanted nothing, Twilight would keep her books, and RD would get the first edition Daring Do novel, and Spike would get the Power Ponies comic.
Season 5: Scare Master: After Fluttershy apologizes for scaring her friends, they tell Fluttershy that Nightmare Night is all about scaring others and how she shouldn't let her fear of that stop her from having fun, prompting Fluttershy to admit that they are right as she is now willing to go out of her comfort zone to not miss a chance to spend time with her friends.
Season 6: 28 Pranks Later-After the zombie prank is revealed, Starlight finds that Rainbow Dash still has goosebumps of what happened and manages to distract the 'zombie' ponies (and Rainbow Dash) to use spell that erases their memory in the style of the ending of the novel/movie Of Mice and Men, making them forget about the entire ordeal and Rainbow's pranking but makes sure for Rainbow to understand to not excessively prank others.