Everyone has different tolerances for risk (and at different times of their life) and different knowledge of how risky some activities are. When I was younger I raced cars and motorcycles, taught SCUBA diving and did some commercial diving, hung from arena ceilings to hang lights for concerts (more scary than actually dangerous I think), and all kinds of things. When I got married I sold my motorcycles (though I borrowed one back once a year for a trip) and cut back on many dangerous activities. When my wife got pregnant I cut back a considerable bit more.

The amount of control we have over how risky something is varies quite a bit. I'd seen enough SCUBA events to know the dangers and practiced it very safely (always with a buddy I trusted, both w/ extra reg, conservative on tables, extra tank dropped down in some cases, etc.). I became more cautious in racing, mostly by sticking to events with competitors that I knew I could likely trust.

Riding a motorcycle on the road in the U.S. (112 deaths / 1b km travelled) is statistically about 50% more dangerous than riding a bicycle (77 deaths / 1b km cycled). (This compared to riding in a car in the U.S. w/ 6 deaths per 1b km.) When you look at the crash data in more detail though it may actually be safer to ride a motorcycle. A much higher percent of motorcycle deaths, about 71% IIRC, have rider error as a primary cause and are thus preventable with safer riding. Bicycle riding is much lower, about 20% to 40% depending on whose statistics though the best is likely from LAB that puts it at 27% cyclists fault. IOW, 73% of bicycle fatalities are not preventable by the cyclist (except by choosing not to ride on the roads) and a full 44% of cyclist deaths are hit from behind or sideswipe.

In the end we have very little control over the risk we face when riding bicycles on the road in the U.S. Our fate is in the hands of people driving cars and perhaps talking on the phone, texting, trying to find something, drinking, eating a hamburger or trying to get something going with the cute person sitting next to them.