Some people have trouble with background checks for reasons unrelated to any events in their personal histories. When I buy a firearm, my check goes through pretty quickly -- 10 or 15 minutes. Other people who have similarly clean records, however, will have to go through a several day waiting period. I suppose there is some glitch in the system relative to their name. Maybe their name is "Jesse James," or "Blue Beard," but whatever the case may be, their purchase is delayed and somewhat inconvenient.

It may also be that a background check tries to determine if any restraining orders or other court orders are in effect which pertain to firearms ownership. I'm only speculating, but imagine an unpleasant separation/divorce proceeding where an estranged wife seeks a restraining order because she "fears domestic violence" from her estranged husband (you did say some mighty cross words to her once, remember, when she threw your chest waders away?). Could this involve prohibiting or delaying purchase of a firearm? I don't know. Maybe.

Again, fortunately I have never had any trouble with firearms purchase background checks, but I have heard they do happen sometimes.