The reason that she'd go on to accuse Evil Career Woman of willing her to slip on glare ice because the alternative of having to admit that she was so pissed off at being accused of trying to destroy someone's marriage to look where she's going is that she's been raised to think a certain way. Michael's struggle with playing the trumpet shows us what that belief is when Phil makes the stupid-ass mistake of showing him what a real master of the form sounds like. While Phil has the same work to win philosophy that his parents have, he doesn't realize that Mike has grown up in an environment where the following belief:
"If doing a certain thing means that I can't have all the praise right now, I should quit in despair and wail about the cruelty and injustice of the world and all the uncaring and horrible people who hate me and want me to suffer and mock me who live in it."
is held as being axiomatic because Elly never quite managed to figure out that people who tell her that her work needs improvement aren't trying to destroy her because they hate her. This is why I almost prefer John's active antipathy to his kids' interests to Elly's poisoned support; at least with him, you know what you're in for. With her, you get mixed signals, hypocrisy and bafflegab.