Your not caring that the project has no value outside of your own head is far different than the project actually having value outside of your head.
I'm glad you enjoy your little sorting project. I've never been a big fan of Solitaire myself, but to each his own.
It sound though, a lot like some of the symptoms of autism:
- Stereotypy is repetitive movement, such as hand flapping, making sounds, head rolling, or body rocking.
- Compulsive behavior is intended and appears to follow rules, such as arranging objects in a certain way.
- Sameness is resistance to change; for example, insisting that the furniture not be moved or refusing to be interrupted.
- Ritualistic behavior involves the performance of daily activities the same way each time, such as an unvarying menu or dressing ritual. This is closely associated with sameness and an independent validation has suggested combining the two factors.
- Restricted behavior is limited in focus, interest, or activity, such as preoccupation with a single television program or toy.