Again I am not really worried about first off I was 42 when I got my first tattoo, secondly today's art is not yesterdays "Sailor Anchor" and again mine are deeply personal and hold a great deal of significance to me just as drum corps is a significant part of who I am today. If all I have to regret at the end of my life is a tattoo then I say I am doing effing great.
I am sorry your grandfather "hated" his tattoo but the real question is why? Was he not proud of serving in the Navy? Did he feel it no longer looked good 50 years later ( he could get it touched up)? Was it something he did while he was NOT sober? Or was it because of the judgments of others who made him feel uncomfortable or awkward about his decision?
Bottom line I don't care if people think its just a fad and it goes, but more and more people I know are getting "inked" for personal, religious, and even fun reasons. I consider and design all my art while sober, and in fact most reputable tattoo artists will not work on someone who is drunk or stoned out of their mind.
However, I understand your thinking might be different you are from a much older generation than myself, so perhaps tattooing was very taboo.