On  a mac if you want to undo the last thing you did select CMD and Z

If you change your mind and want to do it again select CMD and Y…

….Except in Adobe Photoshop, where CMD Z undo is just the last action…

To go back further it’s  CMD ALT Z (step backwards) and  CMD SHIFT Z   (step forwards)

On a PC use CTRL instead of CMD

Who does this?

Anyone who doesn’t want to keep selecting Edit>Undo