The thing is that you don't always get such an easy decision. Sometimes you have to lay up as the course allows, and 100 yards may well be in the middle of a pond. The 7th hole on my home course has a lake that extends from 100 yards to over 125 yards from the center of the green, with a large tree that blocks the green from the left side of the fairway if you get too close to it. You have to not only decide how long a shot to leave, but how far left you want to hit it too. The farther you hit your tee shot, the farther right it has to be to avoid the tree, and the smaller the target becomes between the lake and the rough. You can hit a really nice tee shot, but if it's just a little bit too long and too far left, you have no shot but a pitch out. The only really safe shot is to be sure that you don't hit closer than 140 yards from the green... from that far out you can clear the tree even from the left side, any closer and it gets to where you can't get over the tree with enough club to clear the lake. It's a really nice little 320 - 350 yard (depending on the tees) par 4 that can eat you up if you get greedy (I've made as high as a 10 on the hole).
