With most good labs, if you take the bad prints in, they'll make new ones for free. It will also let them know you care about your pictures and they'll be more likely to get them looking as they should. One lab I used in MA would give most people standard prints (which were acceptable), but if you told them what you wanted, they did a better job because they knew you wanted their best effort. They cared about the output, just not quite enough to do it for everyone. Their best printer left for college and didn't come back, unfortunately.