sympathy for mommy's

So, I think having a puppy in a pet store has given me at least a small amount of insight into what it must be like for new moms and those just-trying-to-be-helpful people.
Every time I go into a pet store with Brody, mostly the people who work there, start drilling me with questions about how I am caring for him. Who's his groomer, do you socialize him, are you going to enroll him in classes, why don't you train him to a litter box, do you brush him every day, do you brush his teeth, don't forget you need to get his ears plucked, it's not humane to put him in a crate, etc. Des was told by a dog trainer the other day the medicine we got from the vet we didn't really need and could have gotten something from a drug store that would work just as good. Umm...do you hold a veterinary degree??
Today, at a different pet store, I was told the food I am feeding him is only made up of fillers and doesn't really have that much nutrition for him. Umm...sorry, it's what the breeder was feeding him.
So I wonder, how do mom's of humans deal with this kind of scrutiny? I imagine you would start to question yourself and your actions and wonder whether or not these people are right.