The Complexity of Undo

Uno is a solution looking for a problem or such. Undo is really complicated to implement. Why? Because people are not familiar with it. And pushing delete and realizing that somewhere you're supposed to find a button that says, oh, I can undo what I just did. That's harder than people actually make sure that they're confident enough that when they're deleting something, they're deleting it. The deleting it is actually... A lot of the time it's not really relevant. If I'm not actually physically interested in it, physically shredded and put through a blender or whatever, I'm actually just don't want to see it anymore. So why do we even have to delete