What are your thoughts on servers who squat next to your table as they're taking your order? I am decidedly against it. It's just a little too casual. And also icky. Maybe if I was ordering fish tacos at some dive at the beach that would be more acceptable. But if there isn't the possibility of having sand in your food then I'd prefer my servers stand upright.
I once had a server sit in the booth beside me. I didn't leave him a tip.