"More importantly, Shelties need "mental exercise." These bright dogs cannot just sit in the backyard and do nothing. To be happy and well-behaved, they require mental stimulation such as advanced obedience, agility, herding, or challenging games you play with them, even if it's just fetching balls and finding hidden toys."
Ummm...the person that wrote this has not met my dog. "cannot just sit and do nothing"--Quincy's favorite activity is laying on the couch. He doesn't even just sit--he lays down. "requie mental stimulation...challenging games...fetching balls..."--I've seen Quincy chase a ball once. ONCE. And that took a year to accomplish. And he doesn't fetch. He'll chase (slowly) the ball, sniff it, and then continue on to the couch where he will lay and do nothing.
So, really, I have a dog who acts like a cat. Which is perfect for me. Although when I see people running with their shelties, I get jealous because it's impossible to run with Quincy. He hates running. It's hard enough getting him to go for a walk unless it's chilly outside. Just chilly--not hot, not warm, not cold - but chilly. If it's anything but chilly, I get him out and walking long enough to do his business and then he "drags" me inside.