B.3. Highly restricted, fixated interests that are abnormal in intensity or focus (e.g., strong attachment to or preoccupation with unusual objects, excessively circumscribed or perseverative interests).

Excel is a highly structured environment that follows strict rules and procedures to generate outcomes, often sorting and making sense of "messy" inputs. Prime candidate for an ASD hobby/obsession.

Good question. I have known many people on the spectrum in my life including several close family members and loving spreadsheets is not something I would attribute to any of them.