Guilt may be a necessary emotion but it quickly becomes redundant when it makes itself a nuisance.
It’s a bit like a star performer in a stage show who makes perpetual and quixotic demands and becomes harder and harder to please. However brilliant at doing their job, they’ll eventually be dropped from the show because they’ll be judged as too costly and troublesome, not a team player and aggravating to the rest of the cast.
While guilt in low doses can be useful, when the emotion takes centre-stage it has outlived its usefulness and becomes a liability rather than an asset. Any emotion can become self-important and narcissistic if it is allowed to, guilt is the leading actor in this sense.