Medical myths

I'm a layperson with no claim to medical expertise. I found the
article interesting and useful, but I think there is an element of
attacking straw men in some items. I comment on a couple of these.

I have never heard anyone claim that shaving makes hair grow faster,
just that it makes it look darker and coarser (which the researchers
acknowledge) and feel coarser (which is consistent with the researchers'
comment that shaved hair is not tapered).

I think most people these days realise that the 8 glasses includes
water in food and drinks.

I also believe that the amount of water in caffeinated and alcoholic
drinks is generally insufficient to offset the dehydrating effects of
those toxins. Repeated experiments indicate to me that drinking large
volumes of water before going to bed and during the night significantly
improves my well-being after a heavy drinking session - contrary to the
claim in the related article on festive matters. THe extra water also
results in a night somewhat interrupted by visits to the bathroom, but
it's worth it. My understanding is that a hangover is largely the effect
of the dehydration caused by excessive alcohol. So, doctors, am I wrong?

Competing interests:
I should really be in bed.