The colleague who always says what everyone is thinking but avoiding is usually the one quietly trusted with the hardest problems, not the difficult one on the team.
What the research found
Amy Edmondson's research on psychological safety, one of the more established findings in organizational behavior, found that teams able to surface problems, disagreements, and bad news without being punished for it consistently perform better than teams where that information stays unsaid. Being the person willing to name the uncomfortable thing is a specific, valuable function a team is often missing, not a personality quirk that gets tolerated.
Why this can land with extra weight for a quieter person
Someone who is usually measured and not the one raising objections is, by default, not read as the person who stirs up friction for its own sake. When that same person does name a hard truth, it tends to carry more credibility precisely because it goes against their normal pattern, not less.
Where to start
This only works delivered well, timed to be useful rather than dramatic, and aimed at the problem rather than a person. Being willing to name the uncomfortable thing occasionally, clearly, and without making it personal is what builds this kind of trust.
Being the person who only ever says what is easy to hear does the opposite, it makes you pleasant and forgettable rather than genuinely relied upon.
Reading exactly when a hard truth is worth saying, versus when it would just be noise, is a judgment only you can make from inside a specific team and moment. What this gives you is the reason it is worth building the habit at all, even occasionally.
There is a specific way to raise something uncomfortable so it lands as useful rather than as complaining, and it is worth having ready before the next moment that calls for it.