Kalista VS Zileas
Conflicted Purpose This one is not a super strong anti-pattern, but sometimes it's there. A good example of this would be a 500 damage nuke that slows enemy attack speed by 50% for 10 seconds (as opposed to say, 20%), on a 20 second cooldown. At 50%, this is a strong combat initiation disable... but at 500 damage it's a great finisher on someone who is running... but you also want to use it early to get the disable -- even though you won't have it avail by the end of combat usually to finish. This makes players queasy about using the ability much like in the optimization case, but it's a slightly different problem. If the ability exists for too many different purposes on an explicit basis, it becomes confusing. this is different from something like blink which can be used for many purposes, but has a clear basic purpose -- in that place, players tend to just feel creative instead.
The damage and stacks add up quick, making Kalista a decisive executor with Rend.
And yet it has a slow on top of all the other frustrating crap in her kit.