Being 66 years old and having practiced law for over 38 years - over 30 of which has been with managerial or ownership responsibilities - I suppose I can offer unsolicited career advice.
People leave jobs. I have dealt with too many departures to count at this point. I have seen it done well. I have seen it done poorly. Regardless, how you end the employment relationship matters - it matters hugely. At the most basic level, the worlds in which most of us operate are actually rather small. That's a reality even in larger metropolitan areas. Never forget that fact.
Many times I have seen colleagues succumb to the temptation of rationalizing their move on the basis that their employer was somehow unfair. Perhaps a moral or ethical failure is "discovered." Hence, someone has a perceived imperative about departing, meaning it’s the only "right thing to do."
Almost always, such posturing is, at best, useless. It is usually misplaced as well.
One of the more remarkable lines I ever heard was someone who justified their departure by saying that since the new firm was paying more, that meant I had been "cheating" on compensations. That's a quote, which was actually expounded upon.
I would like to say my response to that remark (and others like it) was measured and reasonable, but that would not be entirely accurate.
Changing jobs does not require proving moral superiority. Doing so does not automatically mean that you have somehow been victimized.
Changing jobs is a business/personal decision.
If you are departing a job, it behooves you to be businesslike and courteous - even if the other side makes that difficult.
I should probably reiterate that by stating it five more times.
Here's the funny thing: Over the years I have found that a significant percentage of those who got unhappy and left - probably close to 50% - end up making overtures about returning. Often those are oblique or subtle, but it happens all the time.
I have a simple rule: If you left telling me you were treated badly or that we are not good people, there is no return. Period. I might come to be friends with you in a different setting. I might refer you business. You will never be my colleague again.
I don't think my views are especially unusual.
Never burn bridges you don't have to burn.