[n0w]

This is actually a strategy in game.

Go and hit a neutral unit so that you have 2+ hits in a row without your ability/item proc'ing and then save the next hit for an enemy player since your next hit is likely to have a higher chance of proc'ing.

[eterm]

In league of legends you could previously "auto-cancel", and critical hits have different recognisable animations. So if you were about to crit a minion you could cancel the auto-attack and "store" the crit to hit an enemy with it.

I think that's been patched now but it was there for a good while.

[derivagral]

This existed in Dota2 for some time as well; one could use an (illegal) mod to quickly start/stop attacks until it found a crit animation.