This could be for a multitude of reasons: rivalry, you don’t like their players, you want to trade for their players, etc.
For example, aside from wanting the Celtics to fail for obvious reasons, I’m praying on the Raptors’ downfall because if they suck at the deadline then we can try to trade for OG
Nuggets. I despise Kroenke and shitty owners in general and so it annoys me when they’re successful and reinforced in their shitty-ness.