I am not prepared to bash my brains for anything, not even for learning’s sake however precious it may be. From books all I seek is to give myself pleasure by an honourable pastime … If I come across difficult passages in my reading I never bite my nails over them: after making a charge or two I let them be … If one book wearies me I take up another.
I can't take credit for finding this in Montaigne's Essays on my own. It's pointed out in Great Thinkers: Simple Tools from 60 Great Thinkers to Improve Your Life Today from The School of Life.