Annie's flash-tibbers hss plenty of counterplay. Just use telepathy to predict her ult!
I'll be breif. There is literally no way to telegraph when Annie is going to flash-ult you. Now matter how incredible your reflexes are, or how immaculate your positioning is (Unless your champion can attack from 1100 range) or how far ahead you are there is absolutely no way you can avoid getting hit by this AOE hard cc nuke, and inevitably eat her 2.45 ap ratio combo. Can someone please convince me of any meaningful counterplay?
Any of these items will drastically reduce her flash combo kill potentional. Banshees blocks the first skill that she shoots at you, so if she has her stun up, that first ability and the stun will be negated. Quicksilver sash gives magic resistance and allows you to break free of her stun, just be fast. Maw of Malmortius, free 400 magic damage shield + magic resist on top of that. Zhonyas if you're fast enough, similar to the mercai scimitar. And of course Guardian Angel, the second chance. Plenty of counterplay :)