Considering that the advice genuinely helped you, why do you refer to the book as silly?
I think it's been answered pretty well by other people here w.r.t. the mixed reputation of self-help books, with a side of embarrassment for admitting I read one (which is really nothing to be embarrassed about).
Some of them lack science. Worse, some of them are actively anti-science.
I agree that there some great books, with useful helpful life-changing advice.