That slave mindset is not good, though. It's not about not having feelings. It's about ignoring your feelings.
Why do your opinions not matter?
Even better, where did you get the opinions? are they definitely your own, did you choose them from all available options by picking the ones that were best for you, or did you passively absorb them from people who can profit from giving you those opinions?
Conversely, why should they matter? I'm not saying they shouldn't but I think it's worth pondering.