Waiters/Waitresses: Do you treat people worse if they don't order alcohol/drinks?

I'm in The USA if that is relevant in any way.

When we go to a restaurant, I've noticed different service based on if we order alcohol or not, and the service is typically much worse if everybody orders water. I can almost see the cheeriness vanish from the person waiting on us when nobody orders alcohol, or even a non-alcoholic beverage. Typically the groups I go with are smaller (4-5 people) so there is no automatic 18% tip.

Is this difference in service because alcohol is expensive and not ordering it means less tip? Am I totally wrong in evaluating the situation?

I'm at the point where I'm reluctant to go to a "nice" restaurant because of this, as I get better service at places (e.g. a nicer Pizza place) where the alcohol selection is a few bottled beers and there a quite a few other customers who don't order alcohol.