One of the most consistently frustrating and annoying things for me in loot driven games is finding what should be an awesome upgrade that I can’t actually use because of a Resistance conflict in that slot.
For example, a new pair of boots is stronger in every way than my current boots, but it has Fire resist and my current ones have Cold resist. If I equip them, now I have way too much Fire and not enough Cold. Meanwhile, my gloves and belt have Fire resist but would be very hard to replace with similar-but-Cold-resist. I am no longer excited about this otherwise exciting drop - I am sad/frustrated.
While Chaos Glyphs exist as a way to try flipping the resist to something else, they do a poor job of solving the problem because they are too random and can only be used on <T5 affixes.
It would be nice if there was some system, glyph, whatever, that was more workable for shuffling resistances around.