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.
Purity Sue/Canon Sue: Lila. Let's face it, she's just so sickeningly sweet on top of being selfish enough to ask Snoopy to come back with her (despite having a pet already)...and she gets off with it. Feeling no regret for nearly breaking poor ol' Charlie Brown.
To be fair, though, the cat could've been an unexpected coming-home gift from her parents. You never know. And the "No Dogs Allowed" sign? Okay, so maybe they had to give her some fallibility. Gotcha. Still, it's possible she could've overlooked it without warning. Besides, there are ruder characters: Lydia from Charlie Brown's Christmas Tales and Melody-Melody from You're in the Super Bowl, Charlie Brown come to mind.
Tear Jerker: OH, GOD, this movie will leave you in tears eventually, no matter what.
Lila. She made a mistake (and a rather simple one), as noted above, but even so, is anyone else bothered by Snoopy's dancing away with a smirk on his face while she stands there crying? Is this really Snoopy's idea of resolving his affairs with her? Come on, folks.