[@BangoSkank]

[quote]Jack is investigating a grand conspiracy about Arlen.  Maybe about old Arlen history or about Strickland propane or about some big government cover up of something or other.  Maybe he came across Dale Gribble on some deep web site and is convinced Dale "knows too much" and is actually a fed trying to do something insidious.  He could be spying around town trying to gather information but drawing too much attention to himself due to him being impulsive, fighty, and Arlen being a fairly small town.[/quote]

Okay, I didn't mean for Jack to be a conspiracy theorist. But, rather someone who actually understands how things work, and why many things are the way they are. In fact, he'd be the kind of guy who actually goes out of his way to debunk conspiracy theories. The problem is, because most people aren't as well informed on various matters as Jack is; he'd come across as your typical conspiracy nut.

I'd imagine, he gets plenty of hatemail from actual conspiracy theorists calling him either a government shill, or a traitor... And hatemail from people calling him a conspiracy nut, for pointing out [i]actual[/i] shady government practices that boil down to mundane stuff like cronyism, corruption, etc. 

TL;DR He'd be the Jon Stewart to Dale's Alex Jones.

As to your other ideas;

[quote]
Maybe a drinking problem.
Maybe a DUI.
Maybe he gets into a big dustup and ends up in the Arlen County Jail.
Maybe he starts a Fight Club.
Maybe he goes to music shows and sees John Redcorn's Band or Bobby's Band or Connie's Band or Joseph's Band.  Redcorn had similar musical tastes, I could see him or his son being into the same stuff as Jack.
Maybe he runs in to some of the cast at a gun range.  I could see Dale or Redcorn at a gun range.  Joseph too.  Hell all three together.[/quote]

Okay, I do want to believe Jack is more disciplined with his drinking than to get himself into trouble while drunk. He's plenty capable of that while sober, thank you.

Starting a fight club would be too much hassle for him, but participating in one is more his speed. Perhaps he's tailing someone who goes to one?

The music scene also sounds like his speed. That and the gun range idea. If there's anything Jack can bond with Dale over; it's guns.