Who are the best and worst authors?

In answer to the Alternative Read blog hop question, 'In your opinion, who are the best bestselling and worst authors out there?'

I'll start with the worst (that way I can end on a positive - lol!). My current grouse is against anyone who writes self-help books on 'how to get fit in two days and lose half your body weight' Are they sanctimonious or is it me who is tetchy? The latter, probably.
However, I am a little peeved to have accumulated more extra pounds in weight than I care to admit at a time of year when I should be shedding it. So what should I do? Not lie down and read a book, that's for sure.
In fact, perhaps that is how it all started. Holiday reading this year has been a delight and I have immersed myself in novels by such authors as Wendy Holden, Catherine Alliott , Maeve Binchy and Bill Bryson to name but a few. So are they the best authors ever? No. But they are all light and entertaining - ideal holiday reading - even if they have a lot to answer for (Yes, I'm back to the weight issue! Well, I can't blame myself for inactivity, can I?)
So to answer the question and name the best bestselling author. Oh dear, I'm afraid I can't. There are just so many great authors out there. Sorry!