I’ve often seen Buddhists (Eastern and Western, others and myself!) rationalize continued involvement in bad situations under the excuse of “cultivating upekkhā” or “practicing patience” or (worst of all) “exercising compassion.”
So I just wanted to point out that the Buddha often praised good relationships and conducive environments and never spoke in praise of cultivating friendship with fools nor sticking around in environments unsuitable for striving. Bodhisattvas take note: There’s nothing “noble” about self-sacrifice!!
MN2 outlines the difference—what afflictions are to be endured and which afflictions are to be avoided:
What taints, bhikkhus, should be abandoned by enduring? Here a bhikkhu, reflecting wisely, bears cold and heat, hunger and thirst, and contact with gadflies, mosquitoes, wind, the sun, and creeping things; he endures ill-spoken, unwelcome words and arisen bodily feelings that are painful, racking, sharp, piercing, disagreeable, distressing, and menacing to life. While taints, vexation, and fever might arise in one who does not endure such things, there are no taints, vexation, or fever in one who endures them. These are called the taints that should be abandoned by enduring.
What taints, bhikkhus, should be abandoned by avoiding? Here a bhikkhu, reflecting wisely, avoids a wild elephant, a wild horse, a wild bull, a wild dog, a snake, a stump, a bramble patch, a chasm, a cliff, a cesspit, a sewer. Reflecting wisely, he avoids sitting on unsuitable seats, wandering to unsuitable resorts, and associating with bad friends, since if he were to do so wise companions in the holy life might suspect him of evil conduct. While taints, vexation, and fever might arise in one who does not avoid these things, there are no taints, vexation, and fever in one who avoids them. These are called the taints that should be abandoned by avoiding.
So this gives us our measuring stick between patience and avoidance, nibbida versus aversion: are we avoiding this situation because it’s painful or because it’s connected with the unwholesome?
Interestingly, both physical repulsion and moral disgust use the same part of the brain. So, the training here isn’t so much to kill off our capacity for disgust, but is rather to (re)train it to be automatically avoidant of what is unwholesome and unbenefitial. In short, to be wise.
In this way, disgust becomes our ally on the path instead of our hindrance. Aversion becomes nibbida as wisdom flowers.
I hope that helps to clarify somewhat. 