So you choosing to leave is the same as being forced to leave? A boss has power you do not in many ways. They can increase your pay, they can choose the projects you work on and do not work on, they can terminate your employment whether you want it to terminate or not.
Choosing to leave is equivalent to being fired; either my boss or I can unilaterally terminate my employment agreement.
My boss can increase/decrease my pay, and I can either accept or reject the new agreement. I can also demand higher pay or threaten to quit. They can tell me to work on certain projects or I'm fired, I can say I want to work on certain projects or I quit. They can terminate my employment whether I want to or not, I can quit whether they want me to or not.
Employment is a market; a situation characterized by cooperation and mutual agreement. You may choose to pretend you have no agency and are a mere victim to your boss, but I do not. My employees don't pretend this either, which is why I need to keep them happy.
What of that do you have in common with them?