[Jason.]

I'd opt for they took on my least favourite housemate/had an argument with my least favourite.

Both Ashleigh (BB15) and Calum (CBB15) spring to mind.
Whilst I like both of these housemates, I hated how they're popularity increased just because they stood up to somebody that was disliked (Helen, and Perez).

The things that were said on here about Calum, then for people to change their opinion just because he opened his mouth, annoyed me.
You should like somebody for who they are, IMO, not just because they agree with you.

It annoys me when people judge like that.
I also hate guilt by association. A lot of housemates who had potential were killed off very early in BB15, just for being too close with the hated housemate. (Tamara, springs to mind).