I think of hair color like makeup. If you like the no makeup look- good for you but I like to enhance my eyes. If you like gray hair, good for you but I don't.
When I was very young, I had platinum blond hair. It got darker & darker until it was sort of mousy brown in my middle school years. I started coloring it blond until I graduated high school. My natural color was medium brown at that point and not as dull. Every so often, I would highlight during the summer- or whenever I felt like it.
Just like I hated the mousy brown color, I can't stand gray hair. I think I would have to be dead or in a coma to not color my hair. I am 39 and I really started getting a bit of gray about 3 years ago. Prior to that it just was a hair here and there and often blended with natural (or purchased) highlights (unless I yanked it out). Highlights pretty much hide the gray until it's time for my next color 8 weeks apart.
DH is 43 and his hair has thinned considerably and receded some but he has only gotten a few gray hairs at one temple in the last year. He keeps his hair short and it's not as noticeable, though. A guy at his office has terrible color jobs and I'm not sure I could ever talk DH into coloring his hair.
I will say that if you have gray hair, kids think you're really old. There's a lady in our community a couple of years older than my mother who had gray hair really young. She worked at a jewelry store and really had a sophisticated look. When I was young, though, I figured she was older than my grandma who probably colored her hair.
My sister has sort of medium to medium dark brown hair. She was probably fully gray by the time she was in her early 20's. She looks like a skunk if she lets her color go too long. She has very thick, coarse hair anyhow and it is hard to color. She has worn it blond in the past with a few dark lowlights. The gray didn't immediately stand out as soon with blond hair.