If you've experienced a situation like this, you know that foam can be friend or foe. On one hand, foam stops the fish from being able to see you easily. On the other, any subtle disruption in that foam from a fly or leader or line plopping too hard can shut down feeding in a nanosecond. Been there. Done that. Got the T-shirt. What I find most fun about foam, however, is that it often tricks you into thinking the tiny little ripples a bulges you're seeing are being produced by tiny little trout. That's not always the case, and there is a big difference in the amount of jitters you experience when you can size up a trout rising in clear water and when what lurks below is hidden by a blanket of white.