Surveys have shown that millennials are adopting ETFs at a higher percentage than any other generation, whereas baby boomers remain the lowest. To conduct their own boomer survey, Eric and Joel interview the two boomer investors they know best on this holiday-edition of Trillions: their dads. The men couldn't be more different in their experiences -- one is the ying to the other's yang -- and yet both provide some profound insights into the minds of self-taught investors. They also discuss their experiences with ETFs (one prefers power tools, the other plain-vanilla products) and share what's informed their investing philosophies over the years.