Is it just me or are you noticing less and less of an undo option within apps? Back in the day, every last action could be reverted by a control-Z. Even Gmail continues to offer an Undo button but more mobile, tablet, and now PC applications are missing this critical feature.
Yes, you can argue that you can just go get it out of the Trash, or to that folder you mistakenly dropped it in but that is just such a hassle when I simple and consistent Control-Z would get us back to the previous state.
I’m making this point particularly as we start to move to more of a touch screen based experience. My fingers are fat and if I make the wrong move, I would like to correct the action with a single gesture. Is this too much to ask? I think not.
I’m not going to point fingers because I’ve experience this with Apple, Microsoft, & Android applications.
People, without the magical Undo feature, users are hesitant and fearful of making mistakes; it prohibits play and we all know that play is the fundamental way we all learn.
If you experience an application without an Undo, make noise and be a pain in the ass please. If you are like me, it is as important as the On and Off button.
tkonsecurity.com 
Will do Tim, i am a professional pain in the ass!
If only the non-digital world had an undo function. So many less apologies would be needed.