Why want to live long?

I recently started with a new primary care doctor.
After two visits and exhaustive lab tests, he said
I was doing "fairly well' for my age.
A little concerned about that comment, I asked him,
"Do you think I'll live to be 90?"
He asked, "Do you smoke tobacco or drink beer, wine
or hard liquor?
"Oh no. I'm not doing drugs, either."
"Do you eat steaks and barbecued ribs?"
"Not much ... I try to stay away from red meat."
"Do you spend a lot of time in the sun, like playing
golf, boating, sailing, hiking, or bicycling?"
"No, I don't."
"Do you gamble or drive fast cars?"
"No, not at all."
"Then why would you want to live to 90?"