I've done fishing with a fishing rod, and with a speargun.

With a fishing rod, you get to stand there holding the damn thing, waiting for fish to come bite the lure/ hook. With a speargun, you get underwater and go get the fish you want. Meanwhile, you get in a good bit of exercise. I guess it depends on where you're at. If you're in a freezing cold lake with zero visibility, I guess fly fishing is the way to go. Best to go with a buddy, so you can talk about stuff.... or just enjoy the scenery. However, if you're in tropical ocean waters with 50-foot+ visibility, screw the fishing rod. I'll just dive and get me some snapper or grouper. Maybe even a lobster or two while I'm at it.

Now deep sea fishing... that's something else. You go a mile or so offshore and strap yourself in a chair and do battle with a marlin or something of that nature... that sounds a bit more exciting than lake fishing. But this usually is more about the trophy than about eating the fish.