As you get better at your job, people will ask for feedback.
The most powerful feedback is based on data and experience. "Actually, no, we shouldn't put the Crockpots on sale, because every time we run a promo our Crockpot sales have been dwindling, and anyway, the big online store still sells them for less than we do."
These are facts, things we can look up and argue about whether they matter.
It's also interesting to get feedback based on testable hypotheses: "No, I don't think you should call it that, because many of our customers will assume you mean a form of marijuana."
This is only your opinion so far, but without too much trouble, we can dig in and find out if your take on it is widely held.
But often, people will show you something where facts and hypotheses aren't really germane. "Should we paint the door of the building beige or red?" In moments like this, there are three ways to be helpful:
a. You can acknowledge that this is a matter of taste, find out what the boss likes and let her own the decision.
b. You can engage in a dialogue with the boss about what her strategy is when making this decision. Bring facts and data to the table. A thoughtful dialogue with a rational, trusted colleague can open all sorts of doors in decision making.
c. You can acknowledge that your opinion is an opinion, and not try to make it sound like a fact or even a testable hypothesis. "Boss, the logo choice is always a crap shoot, but at first glance, my uninformed opinion is that it's too garish."
All three of these approaches make it far more likely that your fact-based feedback and hypotheses are taken more seriously next time.
[Today's the day that bestselling author Al Pittampalli's book, Persuadable, launches. His new book is a big deal, a research-based, practical guide to help us understand that people who change their minds are actually the most likely to change the world. A must read. Al keeps challenging our perceptions and helping us make a difference with our work.]