If it is truly a passing emotion, there may be no need to express it at all. If it is likely to grow into something larger, then share your feelings and thoughts about the issue while it is small and can be resolved easier (and probably quicker). If you push your feelings down and try to avoid them, eventually, they will explode out more fiercely.
If you feel confused, annoyed, or unsure, silence definitely isn’t the way out. Express your emotions. Talk about what’s bothering you. Don’t just leave it inside and let it start hurting you. Talk with respect and concern, taking responsibility for your own feelings. No blame, no judgment.
(It’s not always easy to find the right moment and words, but you gain a lot by trying. You’ll also start to get better and better at being timely and accurate.)