There are some words in the English language that can mean their opposites, if you see what I mean. I used to know several, but the only one that comes to mind now is ‘Cleave’. Sometimes it means ‘Join’ or ‘Stick to’. It is used several times in the Bible (I mean the real Bible, not the volume of semi-literate drivel now used in most English churches) in that sense, particularly about wives or husbands. But it can also mean ‘Cut’, or more accurately ‘Split’: the sticks of simple chestnut fencing (can one still get it? It was always the cheapest sort) were typically cloven rather than sawn.
‘Quite’ is not quite like that. I don’t think ‘quite’ ever quite means the opposite of ‘quite’, but it quite often means something quite different from ‘quite’, and at least in written contexts it can be quite difficult to tell which of the two senses is intended. ‘Quite’ can mean ‘A little bit, an adequate but not overwhelming amount’ as in ‘I quite like Mendelssohn’s music,’ but it can also mean ‘Completely and utterly’. When the art critic Brian Sewell — he of the strong opinions and mockable voice — was asked on Television his opinion of that German chap who buys human corpses, ‘plastinates’ them and puts them on exhibition, he said he was ‘Quite mad’, and the way he said it left no doubt which sense of ‘quite’ he was using.
But that’s the trouble: in written as opposed to properly spoken contexts, ‘Quite’ can be quite ambiguous, or even quite ambiguous. If I write here ‘Margaret Thatcher was quite mad’ many readers might think I mean she sometimes seemed a little doolally. Only those who know me well will know I mean she was utterly, completely, — quite — bonkers.