Extra low action prevents the plucked strings from oscillating as far as a higher action allows. It hurts fullness and chocks the dynamic range. The strings are hitting the next fret above the fret which is being fretted. Even if you don’t hear any actual buzzing it can actually be diminishing tone. The trick is to go as low as your playing style allows. Very light players with a timid dynamic range can go as low as .060″ treble E string (to 12th fret) and .090″ bass E. We set our new instruments up to .070″ and .095″ but it is conceivable some hard players can need an action height of .080″ to .105″!
That is why I worry a little when I hear about guitar tech’s lowering the action on our guitars – I have seen far too many instruments set lower than is correct. A good tech will educate and confer with the player before randomly lowering the action, and they should have set limits and take accurate measurements before-hand. Of course, for ease of playing, the player usually wants the strings laying on the frets. Resist that temptation!
Also dry weather lowers action and humid weather raises action because the top rises and lowers a considerable amount summer to winter depending on where one lives. Care should be taken in dry weather to properly humidify as well!