None of us being map making geniuses, we'd always end up with something that didn't play well but did have a few "fun spots". Eventually someone had the idea to just cherry pick all those fun spots and Frankenstein together a single map using our individual parts. This map ended up being the most fun we have ever had in Doom.
That's exactly how Half-Life has been made: http://gamasutra.com/view/feature/131815/the_cabal_valves_de...