Counter-intuitive Spell/feature/feat Interactions?

What are some less-than-obvious, counter-intuitive spell/feature/feat interactions you are aware of?

For example: Triton Way of the Four Elements monks can cast Wall of Water and turn it into mobile ice with the Four Elements monks discipline, Shape the Flowing River.

Bear barbarian/cleric(or oath of the crown paladin) multiclasses can cast Warding Bond on a creature, then rage, taking only half the damage transferred to them by Warding Bond (except psychic).

Anything to add to these ideaa? Always looking for new ways to make the counter-intuitive viable and useful.