I do find I can sometimes play a tune better once I remember what it's called.

I heard that! There's something slightly disorienting about having a session go into a tune you know but don't recall the name of. For one thing, I think most of us carry around a mental catalog that sorts tunes by how well we know them. When playing a tune whose name I can't immediately recall, I'm not sure whether it's one I know well, one I learned last week, or maybe just something I've heard so many times I'm able to do a passable job of playing it on the fly. When I remember the name and go, "Hell, you idiot! It's ________! You've only been playing it for thirty years!" I seem to be able to play it with more confidence.