In the brilliant Seven Brief Lessons on Physics which I'm reading right now (thanks to Inaki for the tip) there's a (very accessible) section explaining quantum theory. Building on the work of Max Planck, Einstein wrote a paper showing that light is made of 'packets' of energy. The introduction to the article (essentially the birth of his work on quantum theory for which Einstein would subsequently receive the Nobel Prize) is quoted, and it begins with the humble words 'It seems to me that...'. This is noted by the 'Seven Brief Lessons' author, Carlo Rovelli:
'Note the wonderful initial "It seems to me...", which recalls the "I think...' with which Darwin introduces in his notebooks the great idea that species evolve, or the 'hesitation' spoken of by Faraday when introducing for the first time the revolutionary idea of magnetic fields.'
Often, it seems, genius hesitates.