No, it's not that fast. The process is that the first few months are ok, some signs of improvement, and you convince yourself it'll be different, that he's changed, that things are better with you guys, despite what fans of Chelsea, Utd and Spurs will be saying. "Idiots", you'll be thinking, "it's just that he wasn't at Anfield before! He'd never gotten to coach Mac Allister!" You'll be slighty giddy, hopeful. You'll win one big game that you didn't expect to win, and your tails will be up, at that time you'll be thinking that your doubts and fears about him were unfounded. It's actually ok. It's actually... better than ok.
And then it'll crash and burn in spectacular fashion.