My favorite part is getting lost taking an unplanned turn and in the middle of nowhere you end up seeing a little stream flowing through the woods and you think "hmm.....that looks fishy" but have absolutely no knowledge of the place.
A memory of something similar:
Once, in NW PA, everything was running really, really high. I wasn't exactly bluelining on purpose, but was relegated to fishing small brookie streams. Well, there's one, where to access the best part, you drive the ridgeline above on a featureless dirt road with the window down. At the area I wanted to go, there's a waterfall, and you can hear it from the road. So when you hear the falls, that's when you pull over and park.
Well, on this day, I'm driving, I hear the water, pull over, park, go down. Hmm. No waterfall here. And this stream is a bit smaller than I remember. We must be upstream of it. So we fish down, catch a few, expecting to come on the area I know. But instead, we hit a very large stream indeed. Now I'm puzzled. So we hike back up to where we started, and go upstream. No waterfall, but we're catching a few fish. It's getting late so I take a tributary of that takes us back towards the road, and catch still more fish.
Finally make it back to the car, get out the maps, and realized we fished the wrong stream! The dinky streams were running so high as to make them audible from the road, and it messed us up. Neither the stream we fished nor it's trib were on the fish commission's wild trout list, and the trib was unnamed. They weren't "good" fishing, but we caught fish.
I wrote an e-mail to the PFBC telling them were we found the fish, I didn't get a response. But 2 years later, I saw the stream and it's unnamed trib were to be added to the natural reproduction list.
