You don't have any good answers too.
Shes a whiny, greedy, self centered pony, really...
1) In Look before you sleep you list Rarity and Applejacks "wrongdoings" but somehow you only dislike Rarity because of it? And i don't know why you do not understand that Rarity has a real fear of dirt, that makes it the more great when she actually overcomes that fear for others.
Is how a someone goes into bed really a reason to dislike someone? And why would she go under the table if they could just go inside where it is warm and dry? Would you go under that table and lie in the mud in that situation?
The reason Rarity ignored that tree was because she was unable to cope with all that destruction. She was oversrained by that situation. If you have something that you cannot cope with mentally you tend to ignore that thing in question, like someone whos house burned down, but still tries to sweep the drive way.
2) Spike helps Rarity because he wants to, and because he gets gems, if you dont want that he helps her, talk to him, maybe he will listen.
And the dogs were not so strong after Rarity managed to restrain them a second time... This time the lesson stuck: Don't buck with Rarity. And why not let them work for a while to compensate for their wrongdoings? Rarity had the situation under crontrol, like she said in the end.
3) So you dislike Rarity because she was too generous and gave her fabric away to an old acquaintance?
And you do not seem to understand the whole purpose of the key episodes, every mane6 did struggle with their element, they where supposed to. Why do you only dislike Rarity for it?
Rarity reacted poorly, but only because she thought everything she stands for is a lie, like Suri showed her. She thought that everyone would exploit her generosity, something the mane6 actually did in the past already.
She was hurt and disappointed. That is the reason she reacted like that.
Raritys penance for that was the fact that she ran out of the fashion show, risking everything she worked so hard for in the past to reconcile with her friends. She did more than enough to make up for her failings.
Failings every mane6 had in their key episodes... So, why just dislike Rarity?