When ordering food at a restaruant, should the food come out of the kitchen not as perfect as you like it, it's acceptable to send it back to have it cooked your way once. Should it come out the second time just a bit off but closer to the way you do actually like it, refrain from returning it to the kitchen a second time. As a person aquainted with the food service industry and more importantly a one time cook myself...the second return can only bring about hostility to not only you , by the server and the cook...but may also liberate a haneous expectorant or some other nasty foodie degredation on your behalf.
These people don't make the best wages and aren't actually in the same frame of mind as yourself, along with your returned meal they also have to prepare others' food. The second "I don't like it" is a slap in the face and tolerance basically goes out the door at that point.
I've witnessed 1 return, 2 returns, and 3 returns.... (2 got a re-heat to medium well by way of a 5 second rule violation) (3 got a sneeze after the 5 second rule violation).
Not all places are this way, 4 star dining establishments with Head chefs are above it. If you are at a diner and Mel is behind the counter listening to Flo bitch at him don't send it back.