Win/win solutions don't ever take too long.
Suppose you have conflicting ideas X and Y. Then you can decide: "this would take too long to sort out whether X or Y is better. so I will just do Z right away b/c it's not worth optimizing". Z can be a win/win.
note: Z could be X or Y, but is more often similar to X or Y but not exactly identical. Z can also be some kinda compromise thing that mixes X and Y. or Z can be something else, like a simple, unambitious alternative.
if doing Z is something that the pro-X and pro-Y factions in your mind can be happy with (since they value saving time and not over-optimizing), then you have a win/win.
so that's why win/wins never take too long. the cases where choosing between X and Y would take too long are addressed in this way.
if you cannot find a Z which is a win/win, you have a problem to address there. it's worth some attention. why does one or both factions in you reject every Z you think of? the reason is worth considering more than zero. it ought to be addressed somehow. you need to know what's going on there and come up with something OK (not terrible) to do about it; don't just ignore the problem.