In the interest of making more of an effort to give a decent answer rather than my earlier response, are you talking tournament or cash?
Can we have some examples of of the situations you're having trouble with?
The following is as general as I can make this advice and so I'm not sure it's much use.
Stacking pre-flop is almost never a mistake as the aggressor in either cash or tournament but there's a fair amount of grey area regarding calling a shove.
In cash games how often you stack AK (even unimproved) will depend on the SPR (stack to pot ratio). For instance it's easy to label stacking air as a fish move but assuming the pot was 3bet pre-flop and you missed the flop you've got a decent draw (and card removal on anything you don't have a decent draw against) and you're almost always against a very wide range so your fold
equity is quite high.
Regarding calling 3 barrels with A high, again my answer is only regarding cash games but these calldowns can be fine.
Let's say you're the BTN pre-flop and flat call a CO open raise and take the flop heads up and miss completely. CO cbets and you should be floating pretty much 100% of the time here, turn blanks and CO fires a 2nd barrel that is smallish (1/2 pot maybe), again it's pretty much always going to be a mistake to fold here and then on the river even still unimproved depending on how small his 3rd barrel is and how many draws in his range missed, calling with A high is still sometimes completely fine.
But yes, the people you see doing it are probably fish and it will usually mean you should just start value betting very thin against them.
Please be more specific in your questions. It's hard to say anything useful when people ask such broad questions.