Someone leads out for a pot-sized bet into four people, which should basically never ever be a bluff, and someone calls... so if you shove, you're getting called for sure. That's fine - you have basically coinflip equity against most hands that might call you here, to go with some dead money. But if I have what might be 15 outs to a winner on the flop, I don't want one call. I want five calls!
I mean, if you're getting all in here and you make your flush, you want as many people in the pot as you can get. So I don't want to shove here and only have the one strongest hand calling me. I think I want to put in a small raise, even a min-raise, and get as many calls as possible knowing I'm all in on any turn card.