We did a lot of flying domestically when I was a kid, and I knew my father was very good about maximizing the bills he paid with his Citi AAdvantage card. I didn't realize it until years later, but my father had opened an AAdvantage FF account for me in 1989 when I was 10.
The miles were pretty insignificant, and I burned them for domestic Y travel during college.
Last year I married the greatest girl in the world... who happens to be pretty afraid of flying. I decided I had to figure out a way to fly in J for our honeymoon (LAX->Italy). Within a few months I had added 110k miles to my AA account, enough for 2 roundtrips in J.
As you all know, however, it is addictive. Those 2 J tickets were 600k miles and 14 months ago. 2MM lifetime miles here I come.