Ok, I have a hat that I find important. But for some reason I don't mentally associate it with success or lack thereof. It's just slightly ridiculous looking but comfortable and does it's job well. So it kinda became my "calling card", and I wouldn't be comfortable on a stream with any other hat. But I don't think it makes the fish hit.
On the other hand, I have a slight superstition about whether I have a chew in. The fish can be prefer either way, but they do care, see. So when I'm out there adjusting weight, leaders, tippet, and fly, I'm also adjusting whether I have a lip full of tobaccy. Amazing how many times my fortunes change (for better or worse) immediately after that particular change. And once you know how it is for that day, of course, you have to go through the rest of the day with what works...
And if you happen to be nymphing, and find that a little chaw is the ticket on that day, you can increase your success by spittin a bit of juice on your nymph...