Or rather, whose opinion *should* matter to you?
[Of course, the Lord's opinion of us is all that really matters... but speaking from a human perspective, I continue...]
The opinion of those whom you respect are the only opinions that you should think twice about, in my opinion. (Ha, accidental play on words there!)
I say this because I have talked with so many people who are upset because of someone else's opinion... and this "someone else" is most often someone they don't even respect. Why does that opinion matter to you? It shouldn't. Don't let it.
If you have expertise in some area and someone with less or no expertise tells you that you are doing something wrong... why let that bother you?
With the exception of Biblical moral standards, there is very little 'right' and 'wrong' in this world. There is 'more than one way to skin a cat'... it's okay for each of us to have our own personal 'right way' but it is Not okay for us to demand others do things our way... or cast judgement on someone for having their own 'right way'. (I'm talking about personal relationships here, not employer/employee ones. Of course, if you are the boss and you want things done your way, that is your right and privilege.)
Years ago I was an experienced, successful breastfeeding mama and someone expressly shared strong opinions that I was doing it wrong. It made me so mad. I fumed for days. Then I realized how foolish I had been to allow this opinion to affect me so strongly. The opinion giver had never been a breastfeeding mom as he was a man! Ha! Why did I let that bother me so much? It, obviously, stuck with me and I eventually realized whose opinion should really matter to me... those people that I respect, people who have a measure of expertise in their area. The rest, just let go.