Some ad-libs are OK. But some just take the whole trilling thing to far. Kelly Clarkson can sometimes be a victim of this too, especially on her cover versions on American Idol, and World Idol etc. Christina Aguilera can sometimes be OK. Mariah has toned it down a bit, but I think that's old age ha ha. Keisha from the Sugababes really hurts my ears with her ad-libs. She seems to shriek through them, and purr through all her lead vocals. And luckily for me I hadn't really noticed Rihanna's on SOS all that much, I certainly didn't think they were over the top. In a way I thought they were necessary, to fit with needing help etc.