Targetting dilemma
Say it is lategame, the ADCs are critting big red 600's on people. Yet this Sejuani with 300 armor and 5k HP places herself in front of that hard hitting ADC behind, making her untouchable. If one were an ADC as well, I'm pretty sure that any attempt to get in range to shoot that hoe hiding behind her 4 muscled bodyguards would lead to painful death by nuke and cc. Not even an assassin can do that safely (though he does have a higher success chance). The safest option is to just hit whatever's closest that you can hit safely.
But I still get people arguing over targetting, especially after a lost teamfight. "Y U NO HIT ASHE?" "GG, FOCUS MALPHITE MORE." "STOP FOCUSING TANKS!" I understand Zed blowing an ult on Mundo is a waste of CD that could have killed the ADC but an ADC him/herself values self preservation over going after priority targets in my opinion. If it's not safe to shoot, back off until the heat is off yourself. If it's safe to shoot something, shoot the most valued target that's safe to shoot. Isn't that how a teamfight works? I mean, SOMEONE has to eventually take care of the tank, and the glass cannon ADC is most suited for the task, isn't it?