It is actually optimisim which is why people hate Akali.
You get her to 10% health and she shrouds it sounds like a free kill if you just wait out her shroud. You know she is in there so you wait in there and then BAM she heals back to about 35% health and then starts nuking you with 3 seconds still on her shroud.
It is almost like old Irelia's E where you get her to 15% health and are about to deliver the last two hits to kill her and then BAM you get stunned and you die instead.
Could be worse. Could be like Pyke where you get to a third health while he is at 10% and then BAM 500+ true damage kills you.
So yeah people hate the BAM reversals. They are often predictable but instinctively you just ignore the reality.
But hey, at least it looks like a good idea.
+ several moments, hell probably with everybody in the roster, that random turned a duel. Akali is just broken on top of irritating to play against. I ban her because in my MMR good akalis snowball a lot more frequently and relatively easily due to lack of lane interactivity, and I don't even play lanes. Until her play pattern gets adjusted or she literally sits in the realm of unplayability (and trust me, stats don't mean everything, akali is still very good in higher MMR), I find it hard to believe she'll ever leave ban status unless reworked properly.