Earlier quoted context omitted.
Is that why US service ("checking on the customer every few minutes") is so incredibly annoying...
No. After you've ordered, it is rare to order anything else. You might ask for a refill of a beverage or something like ketchup, but the waiter is not expecting more ordering. It's simply expected by diners that their waiter is there and will help with whatever they need. In Europe you'll wait 20 minutes to get the attention of a waiter for salt or ketchup until your food is cold. Also in Europe this will be describe…
You could ask for the salt or ketchup when the meal arrives.
Also Europeans are not, I think, accustomed to asking for salt, or ketchup, on already seasoned food. So your request is actually unusual.