Just check out the various Jack Russell web sites for a wealth of anecdotes and stories.
Sadly, Jack Russell breed rescue sites confirm that too many of these feisty little monsters need to be "rescued" from the homes of dum-dums who think they adopting a cute cuddly little dog.
Or just go to your local animal shelter and get on the list to adopt/rescue a Jack Russell- chances are one will be dumped there by a frustrated owner.
I'll second that emotion. JRT's are NOT toy dogs - they are hunting dogs, with all that implies. In brief, they are hyperintelligent, hyperloyal, hyperaffectionate, hyperstubborn, and just plain hyper. They are the best dogs in the world, but they are not for everyone.