Whenever i got around 10 BB and am the Small Blind as First In Wiz suggests to push any two cards against average opponents.. The same goes for the Heads Up with blinds like 400/800, even against fairly loose opponents, there's only one suggestion: PUSH

Why's that?

I just can't bring myself to push any two cards as SB with around 10 BB.. maybe when im really short stacked, and then only once or twice during the whole tournament.

Because SNGWiz has tight default ranges in these situations that might or might not apply to your game, and with those ranges ICM says its a push.

Set the ranges to what you think is realistic for the villain you are playing, if its still says push ATC, then you might want to push ATC. There is of course skill edge, which might make you stay away from marginal pushes (check how marginal ATC-pushing your rubbish hand really is), but other other than that: whether you can bring yourself to it or not; +EV = +EV.

As for heads up, I wouldn't use SNGWiz for heads up at all, SNGWiz is good at doing ICM and complex branching situations that involve ICM. Heads up doesn't have those (ICM and situations where different players might call, push, overcall etc). Just get good at playing heads up semi-deep for when semi-deep, and use some nice pushbot chart, which you use and adapt to villains style for when short.

Turn on the Analysis Details in SNG wiz and look at the EQ% column.