So I just started a piece that is giving me a problem not unlike what @Animisha described when she started this thread.
Check out the parts circled in red:

You can see how it repeats throughout the piece, first the RH doesn’t play on the down beat of the measure after the BAB sequence, the second time the RH plays an A on the downbeat. It’s like an automatic physical reaction just to play that A on the down beat, and harmonically and rhythmically, playing the A doesn’t “sound” wrong.
The piece is sort of moderately uptempo, so it moves along at a nice clip, and for some reason, it feels easier to play on the down beat. So I guess I was playing that A on the downbeat more often than not, including in places where it’s not written. I didn’t notice it, and on Wednesday, my teacher said “are you playing an extra note?” And that’s how we found it. So yesterday while practicing, I was having a heck of a time trying to break myself of the habit. Somehow the tempo of the piece seems to make that harder, since I’m sort of flying along… It will probably take another day or two of practice (hopefully not too much more).
I don’t know if I would have noticed that I was doing that without my teacher’s input.
If you’re curious, here’s the original, I think the forward motion of the piece makes it feel intuitive to play that extra note, but of course, it sounds better when it alternates between playing it and not playing it.