You need to ask a better question. One that is less likely to be answered by those questions, you've already got responses, but you seem to skim through them, sooo
Listen, self development is different from spirituality. With self development, you change, or alter your self. You do things to develop.
With spirituality you just cut to the chase. Accept yourself, black spots and everything, and you've reached the gate.(AKA the gateless gate).