For every principle, there’s a variable.
Hard work pays off (except for when it doesn’t).
Being friendly is a great way to make friends (except when it isn’t),
Do what you love and the money will follow (except for when things just don’t work out that way for whatever reason).
Be assertive and people will respect you (except for when you run up against the guy who doesn’t respond to your assertiveness training tips).
Meditation and visualization techniques can help enhance your performance (except for when they just make you cranky, impatient, and annoyed).
These are only a few examples. An exhaustive list would fill volumes.
The general point is this:
Establish a principle and reality will provide you with an anomaly that refuses to be accounted for by that particular precept.
Principles, in and of themselves, are not safe. Every principle has at least one set of conditions that is capable of rendering it inapplicable.
The solution to such quandaries, however, is not the abandonment of all principles. The solution is the addition of critical thinking.
There is no path to personal development that will yield successful results without a vigilante commitment to 1) thinking for yourself 2) weighing everything you learn against your own subjective convictions and experiences 3) experimenting with different approaches even after you’ve had several failures and 4) taking personal responsibility for the outcomes you create through your choices.
If you’re looking for a fool-proof approach to self-help, there isn’t one. Every good piece of advice that has ever been given is fully capable of making your life worse if you aren’t careful, conscious, and creative in your personal application of it.
Good self-help always begins with the self. Each person is, in the end, responsible for dealing with the variables of his own life. There is no system or teacher that can save any of us from this responsibility. The most beautiful bit of wisdom is immediately transformed into an ugly tool of destruction as soon as it is placed in the hands of someone who surrenders this responsibility to another.