I doubt you would be a success in business, considering your attitude towards customers: it’s an “inconvenience” to take food to the customer that she has already paid for??!!
Once upon a time I was a fast food manager. It is an inconvenience, because it takes an employee’s time away from serving other customers. In a busy fast-food restaurant during a meal rush period, 2 or 3 minutes of having an employee off the line can inconvenience a lot of customers.
One shop I managed for a while was in a busy mall — no drive-thru, obviously, but sometimes special orders had to be taken out to a customer’s table to keep the lines moving. There was a dearth of eateries in this mall, so we were always busy, but the Christmas shopping period was especially intense. We had two cash registers, each supported by a line of order-takers and order-fillers working with assembly line efficiency. One time when we calculated how fast we were able to serve customers when we had an unlimited supply of them (they were already lined up at the gate before we opened, and we had to bring down the gate on a remaining line at closing), it turned out that over the course of an entire day, 9AM to 10PM with extended holiday mall hours, we averaged one customer every 7 seconds, so 14 seconds for each line. If I had an employee take 90 seconds to take an order out to the dining room, that meant 6+ potential customers who we just weren’t able to serve at all that day.