AutoCAD has you covered against ill-thought-out object deletions with its "oops" command. Say you delete an object or group of objects, continue working, and then realize that, actually, that deleted object would come in handy after all. Typing "oops" into the command line brings it back without overriding what you've done since. Is it the most honest feature name ever? Possibly.

Today's Tuesday Tips with Frank post on the AutoCAD blog covers "oops" and other commands in more detail.