Guilt is a feeling. It’s often a legitimate feeling, and it’s a signal from the mind/body that something is wrong. The signalling mechanism itself might be broken, which means it’s possible to feel either too little guilt or too much guilt. In both cases, we’re not deferring to some moral authority about what is an absolute, objectively appropriate amount of global guilt. Rather, we’re talking about guilt as a signalling mechanism for influencing behavior. If guilt makes you do things that are in your broad self-interest, it makes you a good person, father, husband, friend, colleague, and it drives you to do things that also make you satisfied and happy, then it’s probably a good thing and it should be a part of your life. If you just need to confess to a priest once a month or you need to have beers with a friend to deal with that, then so be it, that sounds like a legitimate coping mechanism. If having absolutely no guilt enables you to go on and create incredibly amazing things, like iPhones and Facebook, and millions of people are helped as a result, that’s pretty much great too.
And really, that’s looking at it from an outcome-centric POV. The person whose judgement you’ll have to bear is your own. That much seems rather inescapable, unless you’re really disassociative or are able to run away from your own mind. (I don’t think anybody’s ever really succeeded at this and I’m not sure it’s worth trying.) Beyond that, it’s partially up to you, and partially whatever you’ve inherited. If you believe or were raised to believe in a vengeful god, you might be worried about his or her judgement. Then there’s family and friends and peers and “others”. We’re often socialized to care about what other people think, and we seem to have some innate system for caring about others a priori, too. The two are interconnected.
But the point is, all of that is negotiable and navigable. Guilt begins when you feel that you have failed your duty– to yourself, to your family, to your peers, to society, to God. All of those things are really ideas, but sometimes ideas are backed up with violent force or threats– ie your parents might expect you to get certain grades or marry somebody of a certain type, and if you don’t do it, they might ostracize you, make you feel bad, withhold your inheritance, even be violent towards you, etc etc. Beyond that though, once you get into a position of strength, you get to renegotiate what your duty is– to yourself and to everyone else around you. So I think if you want to deal with guilt issues, that’s the sort of framework you have to work with. What is my duty to myself, first and foremost? How do I know if I’m honoring that duty? And then you work your way outwards.
Guilt is an unpleasant feeling, and nobody should feel crippled by guilt to the point where they can’t function, can’t get anything done, get driven to suicide, or simply live a miserable life. Life is just too short for that.