If your doctor told you that you had an illness, you may want to get a second opinion. You get that second opinion from another doctor, not your mom.
When it comes to design, people feel it’s perfectly fine to get your mom’s opinion. Sure, graphic design in not brain surgery, but IT’S NOT JUST A MATTER OF TASTE. REALLY. I know the size of type in magazines and newspapers (it’s not 12 pt), if know what colors read better together, and I’ve done thousands of professional layouts that I’ve been paid for. You could say that I’m an expert.
I’ve never had a client say that they’ve paid another designer for a second opinion before having me make their logo way too big.
Just remember that you have the right to disregard the opinion of your graphic designer, your auto mechanic, your lawyer, and your doctor, but you are dismissing the advice of experts.
Don’t get me wrong, I respect my clients and their personal expertise of their industry and audience, but I just want some respect for my profession. I may just start wearing a lab coat to meetings.