There's obviously a massive difference between pushing all in and calling an all in (poker 101).

Knowing when to push is one thing but I think many people don't have sufficiently differentiated requirements for calling an all in when obviously there is no fold equity and the other guy has already demonstrated strength.

Basically all things being equal (and there are plenty of circumstances when they are not) I will only call an all in with QQ,KK,AA and AK (and QQ and AK are often foldable). Of course if I am short stack or big stack versus a short stack, or if the opponent is a maniac then things change. But I need a really good reason to be calling an all in with AQ or JJ which are hands where the best you can hope for is a coin flip and you are often dominated.