In a book description I found: "This book will definitely lift up your mood and you'll feel capable of achieving almost anything".
As you can imagine the sense has to be made in a positive way (they are trying to sell the book, of course). Nonetheless, being a non-native English speaker and an English student I would have used EVERYTHING -which is what you would achieve reading that book - instead of ANYTHING.
I tried to consult some educational material but the everytime explanation is: "anything is used in questions and negative sentences" but this doesn't help me out in understanding.
Thanks for your clarification