The contribution is brilliant.

Is it that lighthearted (as in "non serious")?

Not necessarily. It might or might not be, depending on the context.

Many years ago I was a graduate student in one of the most boring quantitative disciplines. A couple of times a year there were departmental get-togethers, planned and orchestrated by the department's administrative staff.

The get-togethers included family and SO's. This way, I got to meet the wives of the male members of the faculty.

The wives of many of the faculty members were very very boring. And not just in that they had plain looks - no, a woman can be the life of the party with plain looks, because the personality and charisma are all it takes. They were boring throughout, just positively boring with no respite.

I shared this observation with somebody I was on friendly terms with, with a big question mark at the end.

He said: "This is because the faculty members are RATIONAL". Being rational (and very very quantitative, so they computed the risks and benefits of their decisions) has led them to choose boring women in an effort to minimize the risk of other men's paying attention to their chosen wives.

Rational? Rational. And, agrees with the song.

To be fair, though, the male members of the faculty were also very very boring (looks and the rest - boring in everything), so it is possible that they just could not do better for themselves.