When you attack a tank

Killing a villain with a ult brings a certain, very satisfactory feeling.

Its like clubbing a rabid dire-badger to death with another, even larger, rabid dire-badger.

Tell that to Riven, Zed, or any fighter/assassin that likes to stack penetration.

Late game, they will destroy a tank no matter how much armor they built to counter them. It's the tank's innate mitigation tools that help them survive these days, not armor itself.