It really depends upon the situation you are referring to,.. hands have way different values depending upon the circumstances (ie. is it late stage bubble play of a sng and you're sitting on bigstack?... or on bubble of sitngo and you're the shortstack utg? Is it a cash table and you're in LP with 3 limpers, etc. etc. etc.
I think you need to break the question down a bit so that you can get a more accurate answer about how to play a particular hand.
In general,.. yah.. A-rag sucks. If you see someone entering a pot in EP with A-rag, for sure mark it down in notes (this is the kind of donk who is going to call you down light when push comes to shove in later stage sng play for example).
Is it MTT play you're referring to? A limped pot, you're in LP and are wondering if you should call? ... maybe.
Are you in LP and nobody has entered the pot?.... raise.
Still though it depends on too many factors to give a specific answer... ie. above, 'raise in LP if first in'... well.. maybe not if it's early levels of an mtt cuz then the blinds aren't worth it.
It's kind of situational... what's going on, who's in the hand, etc. etc.
Generally though it sucks cuz as you know, if your A hits the flop and you lead out and get called... what do you do on the turn? Is he calling you with mid pr... or what is he calling you with? Are you way behind right now or ahead?... who knows.... probably behind but maybe not.
If in doubt... dump it. I rarely play A-rag unless situation warrants it.. .ie. it's later stage of a sng or MTT. OR.. if it's suited and stacks are deep enough I'll perhaps call in LP or will call behind other limpers. I hate opening with a limp but depending on table, it might be the right thing to do.
Good advice above about, "don't think about the times you would've won with it had you played the hand,... think more along the lines of all the times you will lose with it." I was in a live tourney on weekend, avg. stack size on table was only 6bb's (yah.. it was a donkfest), EP limper, I have K-rag suited in SB (an easy laydown.. or maybe shove...but not on this table, they're limping AQ+). I contemplate calling (BB is an aggressive flop player). I fold,.. not wanting to shove (oh yah.. I have around 5bb..why am I so short?.. the entire table is, blinds have gone up exponentially). Flop comes K-K-A,.. groan.. of course EP had limped A-rag and BB got to see the flop for free with an A-rag also. They bet pot & call.. back & forth, split pot on river,.. sigh... I would've stacked them both. BUT... how many times would I have just been spewing off what little fold
equity I may have had left?.. most of the time for sure.