It's what's in yourself that makes you happy or unhappy.

People with a grudge against the world are always dangerous. They seem to think life owes them something. I've known many an invalid who has suffered worse and been cut off from life much more . . . and they've managed to lead happy contented lives. It's what's in yourself that makes you happy or unhappy.

Ah, I see you are an actress, Miss Marple, as well as an avenger.

One does not like to make definite assertions unless one has a little more definite knowledge.

Everybody is very much alike, really. But fortunately, perhaps, they don't realise it. - Miss Marple

Her account is that she tried to get out of having to read it, but it was no use."
"And that's fair enough," sighed Craddock. "If anyone is really determined to lend you a book, you never can get out of it!