The "pop up while I was typing and it hit a button when I hit a space" situation is especially painful. I use a custom keyboard layout with lots of layers so it

The "pop up while I was typing and it hit a button when I hit a space" situation is especially painful. I use a custom keyboard layout with lots of layers so it's doubly frustrating for me. I just see a UI flash and I'm like "wtf did I just do?" Any salient state change of important data ought to be reversible in the short term. I'm especially fond of Gmail's Undo Send feature (I think it's a Labs plugin, it's not default iirc). For whatever reason, the brain often finds things it forgot when you actually execute the action. Related, being able to trace what actions were taken is also super valuable. Often this is baked in to the UI (e.g. outbox/sent items, undo menu). Inevitably, this results in a lot of state accumulation, thus disk usage, but this can be handled by manual garbage collection (which is the 2nd step in data destruction, so this can't be undone, so use a warning here) or tunable cache/LRU settings.