If it has tires or testicles, you're going to have trouble with it.

A blunt, comic aphorism that collapses two stereotypical sources of human frustration into one rule of thumb: machines that roll (cars, motorcycles, trailers) and beings driven by sex and ego (men, more broadly animals) both tend to generate “trouble.” The humor comes from the deliberately crude parallelism and the overconfident certainty of “you’re going to,” which mimics folk wisdom. Read less literally, it’s a cynical observation about maintenance—mechanical upkeep on the one hand, and emotional/relational labor on the other—and how predictable complications can be when desire, risk-taking, and wear-and-tear are involved.