ISLA GIATT

The acronym for It Seemed Like A Good Idea At The Time.
First seen 1982 as an opulent over-the-top boat's registered name moored on the river Thames. The owner was on board and we asked him if our guess as to what the name meant was correct. He confirmed. Many of my friends have used the two-word phrase since, for a shortform answer to any question that might deserve it.
Isla Giatt's owner had redundancy pay and a large pension, but was finding it much more costly than he thought, before even registering the vessel on the Thames. Hence its name.

Why buy such an expensive boat that's gonna cost thousanands in mooring fees alone -- then there's licences -- and you'll use it three or four weekends a year!

Isla giatt!