Self-help authors need to understand that people are different, therefore require different suggestions. I read a lot of advice on life, health, work as of late, which are usually geared towards one psychological profile or another that clearly reflect the self-help guru's personal preferences, but not suitable for the general public at large.
For example let's talk about "enjoying your work" issue.
Each MBTI type relates to work differently. Guardians and Rationals don't have to enjoy work, that is, they dont have to enjoy day-to-day grind of it. For them, it's the end result that matters.
If Guardians are providing for someone through their work, and they are seen as the linchpin in their community, they are happy. Sufffering, "sacrificing" for what they do is almost a prerequisite for them. "No pain no gain" was almost definitely uttered by an SJ . If NTs are striving toward some kind of wizardry, building, utilizing knowledge, they are happy.
It's the Artisans who need to enjoy the day to day work, not others. Also, most of the "live in the moment", "wake up to today" kind of suggestions are written by Artisans for Artisans. By the same token, "finding your true self" stuff is mostly for Idealists. Keirsey in his book Please Understand Me II has a few paragraphs on this that I think every self-help guru needs to read.
 After I wrote this I Googled and found that the originator of this sentence, Jane Fonda, was in fact an ISFJ. Some might think she was an Idealist, but remember, Guardians continue whatever cultural environment they were born in, and father Henry Fonda was active in social issue since his youth. At age 14, he saw the lynching of a black man that so enraged him, that a keen social awareness was present in him for his entire adult life 
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