Most half-breeds consider themselves as trapped between two worlds, unable to fully fit in with either side. A half-orc may lack the full effect of their orcish bloodfire, while a half-high elf lacks the longer lifespan that allows their elven side to focus on the minutia of life. But the same goes for their human side, the pure mundanity of a human gets nullified when genetically intermingled with a magical ancestry.
These differences aren't just on their physical characteristics, but also when interacting with members of their parental ancestries. A half-wode elf raised among humans might not understand the intricacies of the wode they are walking through. Or a Mul raised with dwarves can help in mining by channeling their human endurance. But the dwarves might not understand why the mul can't handle all the heat of the forge that the dwarves resist with their tough skin.