Dumbledore is the clearest example of this; despite knowing every detail about where and how to destroy the Horcruxes, he did not inform Harry right away, instead of leaving him hints and hoping he would piece them together. Why would he do such a thing?
The most amusing thing is that in Spiderman: No Way Home, Dr. Strange casts the magic that opens the Multiverse, but he now forgets about it because of the spell. The portrayal of evil strange by Benedict will dominate the portrayal of normal strange.