The barking shows he is worried you're not going to come back. I'm afraid that the only way really is to keep leaving him outside shops when you go in until he knows you will always return. Good luck.

I believe so, yes. I got a rescue dog years ago that had been abused, American Bull. He was very nervous at first but as the years went on he became much more sure of me and strangers. He was a great dog and I would have trusted him with anyone.

To a point but dogs that are genetically lively won't necessarily calm down until they get a bit older. Terriers are a prime example of this.

In some cases, it's just having the patience to work with them to train them that certain things are a little over the top and that they should calm down but in some cases, depending on the breed of the dog it may be difficult and they may not calm down no matter how much you try to be honest. In terms of barking a lot outside of a store, this could be because they are worried you may not come back, the more you come back and they see that the more they will know they are not going to be left and they should stop. 

Posted by: @woof

↑

My dog is a pitbull x Jack Russel. He is so loving but wants to jump up and say hello to guests (he doesn't leave them alone). We also can't leave him outside a shop without him barking like crazy. Anyone have any advice?

My father's dog is also a pitbull x Jack Russel. It's always very stressful keeping him in check. Menh, the excessive barking can be very annoying and frustrating. I never have rest at home whenever I go visiting my dad. 

Unfortunately, I don't want to have any business to do with a crazy breed. They are dangerous sometimes and I don't want to put myself at risk of getting hurt. I was pushed down by my friend's dog which wasn't a happy ending for me. I had a concussion as a result of hitting my head hard on the canvas.