We should accustom the mind to keep the best company by introducing it only to the best books.

What you read is who you spend your hours with. A mind takes on the habits of the company it keeps, the level of argument it hears, the standard of sentence it gets used to, and none of that is conscious. Poor company does not merely waste the time; it lowers what you expect to find.

Have a look at what actually went through your attention last month rather than what is on the shelf. If most of it was cheap, put one thing of real quality into the rotation and give it the good hour of your day. You will notice the difference in how you think within a fortnight.