This one is one of my 3-4 favorites, but I don't use it every day, or even on any kind of a "regular" basis--just every once in awhile, and I find it boosts my mood, performance, thinking, and the quality of my relationships with just about everyone.
MOST of these aren't really designed to be used all the time, or at least that's my understanding. You only need to use them once (there are some exceptions--if they say to use them x times a week, etc.). I think if you use them too much, your subconscious starts to give you the raspberries (aka bronx cheer). Just my experience, yours may vary.