What life lessons are unintuitive or go against common sense or wisdom?
I hate to be negative and there's some good advice here, but really a lot of this is just replacing old unresearched assumptions with newer pronouncements that are similarly without any reference. At best these are left un-sourced, at worst they seem to be based purely on personal experience. Yet most of these are or could be topics of unbias study. A few examples:Buy a nice bed.  Buy a very nice mattress and high-thread-count sheets.  You will need to test out a variety of mattresses to find the one that fits you best but if you find the right one, it will greatly enhance the quality of your sleep, and subsequently, your waking life.Why is it that more expensive mattresses = better sleep? Cite the evidence showing that high thread-count sheets = better sleep, which in tern laeds to improvements in waking life.You can accomplish more if you work less and sleep more. Hypothetically a well-rested person working 55-hour work weeks can usually outperform a sleep-deprived person working 80-hour work weeks in terms of quality, all else equal (specifically for knowledge work).Hypothetically this isn't true at all. Is there evidence to support this hypothesis or not? If not, this adds nothing to the debate.You can pay the farmer, or you can pay the doctor. Prevention (i.e. good diet and food ingredients) is an order of magnitude cheaper than treatment (most age-related diseases are correlated with poor dietary choices).This is trite and catch-all. What is good diet? There is no common agreement (see: high carb/high protein/high fat discussions). Show the evidence that this is 'an order of magnitude' cheaper than treatment. What are 'good ingredients'. You recommend free-range meats? Grass-fed beef? Locally produced? Define 'good'.A cheap chair and mattress may end up costing you 10-20x in doctor's bills.Says who? 10-20x seems pretty specific - what's the citation on that? A 'cheap' chair - so is price the only metric? Any $2000 chair is worth it and saves money on doctor's bills? Doesn't it matter how often i spend sitting? Could there not be cheap chairs that are actually better than many expensive ones? What's an 'expensive' mattress?Spoken communication has a massive non-verbal component. Study body language and you'll be pretty shocked at how often peoples' spoken words contradict their telltale non-verbal cues.Citation please. A lot of the 'non-verbal communication' stuff (read: NLP) is considered unscientific gumf.Don't get me wrong, there's some great advice in here. But around half is stuff that can be scientifically demonstrated and just off-handedly saying something is invalid whilst proclaiming the opposite without providing any citations is counter-productive. It just encourages "common knowledge" of the same old wives tales and folklore that it itself is trying to counteract.