WHEN IT COMES TO financial questions, there are two common reasons people disagree. Sometimes, they disagree about the facts—whether, say, interest rates are headed higher. But sometimes, people disagree for another reason: They see the world through different lenses.

Last week, I mentioned that Ray Dalio, a prominent hedge fund manager, had recently said that bonds “have become stupid.” I disagreed, but not because of the facts. There’s no disputing the impact of today’s low rates.

I JUST HAD MY SIXTH bicycling accident—which made me think about my investment portfolio.
I started cycling seriously in 2005, when foot problems forced me to cut back on running. That was the year I bought my “starter” bike—part aluminum, part carbon—purchased for $1,000 from a bike shop that was going out of business. Within a few months, I added the special pedals with the shoes that clip in.
Early on, I had my fair share of embarrassing falls,