Ok I'm just gonna put something out there, cause I've seen it way too often now.
Please.... PLEASE, for fuck's sake. If you're playing gnar and you're about to die while your rage bar is full, DON'T THINK, just press W and get yourself 650 extra hp instantly, stop waiting for the transformation to come by itself.
Your mini gnar W is a passive, it's never on cooldown, it's practically the no brainer spell to use when you're about to die, USE IT!!
Good?