The Cavaliers lost, so LeBron never revealed it.
Maybe one of the Warriors was wearing his shoes.
LeBron, via GQ:
When I was a kid and I used to see guys wear MJ’s shoes when they played against MJ, and I was like, “MJ got a little mental edge over those guys.” So for me, now being in that MJ class, I’m like, if I see a guy wearing my shoes, if he’s not like a good, good real brother of mine – because I’ve got some guys that’s Team LeBron and that’s what we do – but if you’re just a guy that you just actually go to Foot Locker or somewhere and you just go get a pair of Brons and you want to wear them on a Tuesday night against me? I’m gonna bust your ass. Straight up.
This is a manufactured source of motivation (literally), but whatever gets LeBron psyched up, excellent for him. Great players have little trouble finding perceived slights to pump themselves up.
And this one comes with the bonus of generating more money for LeBron.