I once heard a song lyric that went “I’m gonna let my yearning shine”. I thought it seemed like a good idea, so I tried it. The end result of that is a mental layer/object that burns itself and others, is spikey, and has little to no energy to correct itself. You probably have areas like this within you now, but they hide their destructiveness behind unchecked desire. Even the desire for all beings to be blamelessly happy can be corrupted in this fashion.
Let’s say you’ve found one of these and can see that it is hurting you, others, or both. You realize that it is an unskillful action with painful results, painful consequences, so you want to desist. Let’s further say that MN 20 has failed. I recommend the following plan of action, drive out the thoughts that support the yearning with “May all beings be blamelessly happy” then regard, look at, and inspect the allowing of the yearning to shine in such a way as to impress upon all parts of yourself that such yearning shining is blameworthy, then go back and forth between the two. Replace all thinking in the area with goodwill, then mark yearning shining as blameworthy. Keep alternating until you spontaneously generate the desire to desist shining in that destructive way. Finally pay attention to your breath and the part of the mind that is shining with an unholy light, and connect your breath to it. This will make your breathing heavier. Now breathe in a way that gladdens that part of the mind without stupifying it.
When you have enough practice, you will be able to just look at the problem and tell yourself “That’s not OK” and it will dissipate. Another way to talk about this phenomena is having a shit eating grin.