His whining makes ME want to whine!

I've been listening to Niz whine for the last two years... He doesn't whine as much inside the home anymore as long as we keep his supply of beds steady and fluffy, but whenever we're out and about or in the car, he's a whining machine. With Niz, he's either bored or stressed if he's whining--it's a form of complaining (he has several forms of complaint!). He has to be either eating, walking/running, or being petted. Otherwise, he's whining. Whines when he's bored in agility class, whines when we're standing around on a street trying to figure out where to go eat and he has to stay still, whines from the SF bay area to south lake tahoe in the car. When I took him to Paco Collars one day (I used to barter there in my free time), Niz whined from 10 am to 5 pm--he drove everyone mad. If he wasn't getting attention, playing with another dog, or eating something, he whined LOUDLY and constantly. SO will usually start petting Niz or giving Niz attention when Niz's whining gets to him. Niz isn't exactly underexercised as well. He walks 2-3 miles a day, hikes 5-10 miles a week, and has an hour and half long agility class once a week. Sometimes he carries 5 lbs of groceries 1 mile home (if he's sulking about having to carry stuff, I'll carry most of them instead).

There are so many things I'd do differently from the get go if we got another dog... I know I screwed up so badly with Niz on many different levels. I focused purely on his dog reactivity and basic obedience and didn't even think about impulse control, work ethic, focus/motivation, and especially whining!!