GSBI
acronym: Good Sounding Bad Idea. An idea that sounds exciting or plausable, but upon further thought or execution is revealed to be astoundingly dumb and/or dangerous.
1 - Brian suggested all 20 of us go to the party, when only he was actually invited.
2 - Cat decided to ride her bike to school as exercise, disregarding the fact it was 10+ miles away and she needed to be there in 30 minutes.