I could not get my perfect-pitch addled brain to play a note I knew was a D as if it was a C. Nor could I get my guitar playing brain to ignore the fret markers. It's weird, I know, but remember I also have my DVDs and CDs in alphabetical order. And if I bought a CD by Notes Norton, I am so OCD that I would move every CD after where Notes Norton falls alphabetically in my collection back one slot so that CD was in proper order. If I bought a CD by Adam Ant, it would be a 2 hour project for me to move about 700 CDs in binders all back one slot so Adam Ant was where it belonged.
I do understand that there are people like you. And I do understand that their mind works that way. I guess I also do have corners in my mind that are more rigid, but some areas seem to work fine with a relative starting point.
I had to play some songs in so many different keys or transpose them on the fly from sheet music
that I play in the key of "C" on any position of the fretboard. Back in the 1970s my guitar was constantly tuned in Eb. That probably helped also.
Transposing on the fly causes me to have a lot more trouble on my piano-accordion. It is much easier on a button-accordion where you play the same pattern on just a different location of the button (?) board. (I don't have one so this is no option for me, but I have that experience from playing my accordion's bass section.) Maybe I should devise an Irving Berlin type accordion.

I also have my CDs and vinyl's in strict alphabetical order, some exceptions where an artist has changed names occur, but I left room to insert CDs without moving all the ones after that one. Adam Ant would cause me to move about 30-something CDs on the shelf -- I don't have CDs in binders -- and I don't have a shelf with molds for each CD so I had to move them individually. It is a wooden board that has a slightly smaller depth than a Jewel case is long, so I just push 'em a little to the right.