I don't like going to classes since either a)I haven't prepared, in which case I don't get much out of it, or b)I have prepared, and the class feels terribly sl

I don't like going to classes since either a)I haven't prepared, in which case I don't get much out of it, or b)I have prepared, and the class feels terribly slow - perhaps one point I had a question on will get addressed. Classes where reading the book doesn't lower the information content to 0 are best.