Therapy can only work if the patient will put in the work. It is effective if you are willing to put in the deliberate and painful effort of growing the fuck up. A good therapist will force you to confront your own failures and inadequacies and ask you questions that, if you have any capacity for honest self reflection, will probably piss you off by making you realize your hypocrisy or motivated reasoning. It's not fun. It's hard god damn work, but if you are willing to do the work and you have a good talk therapist you can probably overcome most things.
Therapy fails for most people because they don't actually want to change anything about their life or their thinking and most people with fucked up psychology are genetic refuse and were destined to a life of misery anyway, so if it doesn't work for you after sincere, earnest and sustained effort... Don't reproduce, please.
If you are holding onto resentment and anger it's your fault, either in the sense that you have the capacity to let go and pridefully are unwilling to due to a lack of maturity, or you simply aren't capable of it. Sorry, some people are just brain broken.