Seemed like a good idea at the time

a valid excuse for a really bad mistake, can only be used once

Wife: I cant believe you had sex with those two strippers, then you had the nerve to bring them to the house and make them breakfast.

Husband: Seemed like a good idea at the time.

Wife: I bet it did, it was a bad idea and you are a ass hole for thing it was

Husband: Well, that did not cross my mind at the time. I never banged to hot bitches at the same time and two bitches at the same time is always a good idea.

Rumored to be what Bill Clinton said when asked about Monica Lewinsky during his 1999 impeachment hearing.

Seemed like a good idea at the time by Dave Lickersnach April 8, 2015

Good Idea Fairy 

A mythical creature that causes upper level management to impose changes to standard operating procedures in an attempt to fix something that wasn't broken in the first place. These changes usually inflict undue stress and/or hardship on subordinates while having no negative effects on the decision maker.

Origin: US Military

The good idea fairy must be hanging out in Mr. Smith's office again. He just decided that we need to change the font on our 75 slide power point presentation to sans-serif 16.

Good Idea Fairy by SOCM Doc January 11, 2014

good idea fairy 

Military term; An evil mythical creature that whispers advice and ideas into the ears of military leadership, causing hundreds unnecessary changes and countless wasted man-hours every year. The Good Idea Fairy should be shot on sight if she is seen in your area.

Great! The CO has says that we need to provide a 24 hour guard over the weekend for the empty tents out on training area 17. He must've been visited by the good idea fairy.

good idea fairy by Trav September 27, 2004

Good Idea 

Actually a really bad idea

Person A: You know what sounds like a good idea?
Person B: What?
Person A: Robbing that bank.

Good Idea by Tommy Scofflaw December 24, 2007

good idea fairy cut-off date (GIF-COD) 

Military term: The absolute, iron-clad, no-bull date/time when any visit by the good idea fairy will not be tolerated by anyone for any reason. For most reasonable people this is not later than the time an operation plan or order is published. For senior officers and politicians this is only a hypothetical moment that never arrives.

"The good idea fairy cut-off date (GIF-COD) for this operation is the date we issue the order to the units," said the Commander. "I will personally kill anyone who suggests anything after that."

and;

"The attack was going well until the good idea fairy struck. They failed to establish a GIF-COD.

good idea fairy cut-off date (GIF-COD) by Baghdad Bob May 2, 2006

not a good idea

Defining words on urban dictionary rather than doing your homework.

See also : running out of precious time

I'm doing terribly at university, my math assignment is due tomorrow morning, it is not a good idea to be on this site right now.

not a good idea by TheCupIsHalfBowl May 14, 2018

good idea bus 

Military term; Primary mode of transporation for good idea fairies. GIF's usually come around in groups, hence the need for a bus.

Wonderful! The CO has said that we need to update our communications to the field daily in order to accurately reflect the current messaging and strategy from the command. We also need to update the messaging on the web site to reflect this directive. The good idea bus must have stopped down hall.

good idea bus by Jester2120 September 15, 2006