These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Tear Jerker: Season 2 end gives a soul-crushing separation of Wukong and Ahri with Ahri once again going back to square one in her quest to find true love. Although afterwards, comes a Heartwarming one when turns out Guan Yin thinks Wukong hasn't repented fully from his mischevious way and dumps him into Valoran forever, allowing him to reunite with Ahri.
The Scrappy: It looks like they're trying to invoke this on Teemo, by giving him a whiny pervy kid voice, being an ATM on Noxus' side (or so Twisted Fate said), his presence was what enables Master Yi to defeat Singed & co., crying on a drop of a hat nearly on Amumu's level, only in the League to take pictures of girls and by the end of Season 3, Tristana announced him 'the biggest bastard in the world'.
The Woobie: Regardless of her positioning as a villain, Leona had it rough, living her life with nothing but insults and no friends except Pantheon. And just when she got her power boost, she ends up on Gangplank's gang and being the bad guy.
Ahri is also played up more tragically and sympathetically, with her quest trying to seek love becoming very tragic and her tale with Wukong nearly ended tragically and only fixed via Deus ex Machina.