What's a bright idea you've had which turned out not so hot after all?

Something you thought was a good idea to do, but afterwards, regretted it because it didn’t turn out as you had expected? Does not have to include bad results, but it is recommended.

It can range from the harmlessly comical to the deadly serious. As much as you’re willing to share.
Perhaps you thought it would be good to cut your own hair, but then the haircut just really sucked. Or maybe you thought it would have been splendid to try and scare a policeman. Then someone had to pay bail to get your ass outta there.
Did you think it would be brave of you to start chasing a wild animal? Did you think making a divorce joke was funny?
Ever confronted an actual, legitimate samurai? Ever drank a whole crap load of maple syrup just to show off?

Anything. ANYTHING. Share your stories, if you’re inclined to do as such. Thanks bro, later. :)