Ref to your observation about temporarily-deleterious mutations: I'm beginning to think most of mathematical evolutionary theory is a dead end. Lynn Margulis has a similar view:

“The neo-Darwinist population-genetics tradition is reminiscent of phrenology, I think, and is a kind of science that can expect exactly the same fate. It will look ridiculous in retrospect, because it is ridiculous. I've always felt that way, even as a more-than-adequate student of population genetics with a superb teacher — James F. Crow, at the University of Wisconsin, Madison. At the very end of the semester, the last week was spent on discussing the actual observational and experimental studies related to the models, but none of the outcomes of the experiments matched the theory.” source

I completely agree with your opinion on rampant adaptionism plaguing discussions of every human trait from preferences in sex-positions to nose-picking. “The days when we roamed the Savannah” seem to have as much a sway on today's thought as repressed childhood sexual urges did about a century ago.

A personal favourite of mine is this infernal 'pattern-finding' business. “It was safer for your ancestor to assume that a shape he saw in the bush was a tiger than just a random shape, and therefore today you [insert trait to be explained here]“. It might very well have been that that poor sod saw so many tigers in so many bushes that he crushed his balls with the same rock Mr. Bullfrog was being serviced by in the last paragraph and excused himself from evolution.

Most of these explanations also don't take into account deleterious mutations that may end up greatly improving the fitness of the organism in the long run (get past 'local minima'). Ultimately, all of them are patently unfalsifiable, and that about turns any discussion into a matter of taste.

Ref to your observation about temporarily-deleterious mutations: I'm beginning to think most of mathematical evolutionary theory is a dead end. Lynn Margulis has a similar view:

“The neo-Darwinist population-genetics tradition is reminiscent of phrenology, I think, and is a kind of science that can expect exactly the same fate. It will look ridiculous in retrospect, because it is ridiculous. I've always felt that way, even as a more-than-adequate student of population genetics with a superb teacher — James F. Crow, at the University of Wisconsin, Madison. At the very end of the semester, the last week was spent on discussing the actual observational and experimental studies related to the models, but none of the outcomes of the experiments matched the theory.” source

I completely agree with your opinion on rampant adaptionism plaguing discussions of every human trait from preferences in sex-positions to nose-picking. “The days when we roamed the Savannah” seem to have as much a sway on today's thought as repressed childhood sexual urges did about a century ago.

A personal favourite of mine is this infernal 'pattern-finding' business. “It was safer for your ancestor to assume that a shape he saw in the bush was a tiger than just a random shape, and therefore today you [insert trait to be explained here]“. It might very well have been that that poor sod saw so many tigers in so many bushes that he crushed his balls with the same rock Mr. Bullfrog was being serviced by in the last paragraph and excused himself from evolution.

Most of these explanations also don't take into account deleterious mutations that may end up greatly improving the fitness of the organism in the long run (get past 'local minima'). Ultimately, all of them are patently unfalsifiable, and that about turns any discussion into a matter of taste.