Which rapper has the best ad-libs that actually add something to the song

Not just filler, I mean ad-libs that genuinely change how the track hits. Like when Pusha T does that "YEUGH" it adds this whole layer of menace that wouldn't be there without it. Or the way Jadakiss laughs. That laugh IS the energy of the song half the time.

I was thinking about this because I was listening to some older Three 6 Mafia stuff and Juicy J's little background ad-libs are doing so much work. They're basically a second vocal track that tells you how to feel about what's being said.

But then you got guys where the ad-libs are just... there. Like they're checking a box. No shade to anyone specific but you know the ones. Just a "yeah" or "uh" every four bars that adds nothing.

Who do you think actually elevated ad-libs into something that matters? And is there anyone whose ad-libs you think are overrated or actually take away from the song?

Also curious if there's a generational split here. Feel like the role of ad-libs changed a lot from the 90s to now. They went from being background texture to sometimes being the most memorable part of the whole track.