Which is worse?
Finding a book you love and then hating everything else you try by that author, or
Reading a completely disappointing book by an author that you love?
On the other hand I'm devastated if a loved author has an off day, to the point that I might not actually admit it, even to myself. I had this disaster with Mary Stewart. At the risk of offending her many fans I must admit that Stormy Petrel and Rose Cottage offered only vestiges of her former glory. I know she was in her 80s when she wrote them and I tried so very hard to like them but to be honest they were feathers compared to the gold of her Merlin series and earlier romance/crime fiction.
I read them with my Mum, we were both fans, out of loyalty but we decided if there were any more to come from Stewart's pen we'd probably not read them - it was like loosing a friend.