~When fishing a lake with an algae bloom, reduce or eliminate the number of knots in the over all leader. They collect scum. A one piece tapered leader or a uniform length of leader are suitable for descending down through the bloom to the feeding trout, just beneath.
~Indications of OCD: spending hours on a calm, still, smooth surfaced lake; sun high; hot, very hot. I have spent countless hours fishing such waters, picking up a small trout here and there. Short of doing recon on the contours, weed growth, identifying the drops, shelves and stumps there is little benefit to spending hour after hour out there. There are other activities back at camp and in the area that may better occupy that dead time on the water.
~Are the fish refusing my fly? I have changed flies 6 times this past hour. Could it be the presentation/line selection and retrieve are not balanced to the flies or to the location you are fishing? As enjoyable as it is to use, the floating line cannot be your primary line on a lake if you intend to fish the depths. Research clear intermediates and faster sink rate lines for presentations beyond the shallows. Once the fish move off the shallows (sun rising, water calming, hatch ending) the waters just past the drop off should be explored with sinking lines.
~Presentation…the retrieves: it is nice to bob about out on a lake, kicking, rowing or drifting along in a day dreaming daze. Lost in thought and picking up the occasional fish. Again, considering the pattern you are using, what are you imitating and how is your presentation copying the real life movements of that food source: bait fish, leech, vertically ascending Chironomid pupa, emerging Callibaetis, diving egg laying Caddis, swimming Damsel headed for the reeds? If you are satisfied to kick along the edges of the drop then at least vary your retrieves to provoke a take.