Yes, a lot of my reasons for not going gray are professional, although in my new field, "elders" are actually respected and age did not make it hard for me to find a job, although my resume is nicely doctored, etc. But, my own self image is a good deal of it. I've always enjoyed looking "younger" than my age, and given the fact I am in good physical shape, I think a lot of my self image is wrapped up in this. My skin is not as perfect as it could be (like Emily!), and I have deep laugh lines, so I think adding gray to that would certainly ramp up the "old" factor. I guess I am lucky that I have found a coloring solution that I only need to do a few times a year. Keeping my hair short requires a cut every month, and while it's a pain, it certainly outweighs the factor of having my hair hassle free, in terms of not having to use styling implements, and time in the AM, let alone the ease of making it look good when I take my helmet or ski hat off.
I like to say my water bottle is my favorite styling implement!
AZfiddle, I do think that being around middle school kids, teens, etc. makes you more aware of how "old" you look. I've been around kids/teens all of my life and it has kept me young in many ways.