Out with Dm today and my young DC's. There is a particular cafe that we really like and hadn't visited for a while. Went in and there were not tables so we said we would do some more shopping and then come back to see if any were free. Went back about 30 mins later and we see a table of 4. So we went straight to it and sat down/took coats off etc and went up to order.
At this point we realised a couple at the counter were complaining about us to the waitress. Apparently they had been about to sit at our table and as it was the last one available in there they now had nowhere to sit. Staff were very good and moved things around to get them some chairs but they spent the whole time in there tutting and giving us dirty looks.
My logic is that when going in to somewhere busy we always find a table first and then order. If we waited in line with the kids and then went to find a table and couldn't get one we would be stuck as the kids are too young to take the food or drink as takeout. But then I did feel really uncomfortable and that maybe we did something wrong.