when i started with the T,I i been told if the winodds are bigger then potodds then you cant loose in the long run
i concur though i would advise you not to take the displayed winodds in TI at face value (i mostly mean preflop, though also post-flop as TI counts many outs that are prob. dead). there sometimes are weird winodds of 2 or 3 %, though of course in a heads-up situation no hand plays quite that badly. so you should have some general understanding of the odds of live-cards, undercards, overcards, dominated cards- make an educated guess of your winodds and then see if you have the proper odds to call.
your first post is a bit confusing and it would be easier to talk about certain hands you found yourself wondering.
it most certainly is ok to fold ATo vs a push that doesn't give you very good odds, in fact i think most of the time a call with ATo would even be wrong. generally speaking i would try to avoid calling all-ins anyhow, and instead try to be the one pushing.