True. A good example is the genes for blue eyes and blond hair. They are recessive genes. My dad has blond hair (now greying) and blue eyes, he is of Norwegian descent. My mom has black hair and dark brown eyes, she is of Korean descent. My hair is black and my eyes are dark brown even though half of my ancestry comes from my father.
You also have to consider that a mutation that appears “neutral” (not having any observable effect) might be expressed in some future generation when it comes into combination with a different gene.