Breast milk question

So I know that breast milk is amazing stuff and all but why do I keep hearing people saying that they don't even want to loose one precious drop of it? I mean this stuff keeps making itself. It's literally an endless supply. If I spill one bottle of milk is it really that big of a deal? I know for women who go to work and store excess amounts it might matter more but for me I am not convinced that it's that big of a deal. Now when I formula fed my previous children if I spilled that stuff you're darn right I'd be upset because that stuff cost a fortune. Just wondering what other people's opinions are on it.