Satisfied Feelin' Lyrics

[MG:] Hmm hmm hmm hmm
[BOTH:] People are wonderin' about the change that's come over meMarvin Gaye - Satisfied Feelin' - http://motolyrics.com/marvin-gaye/satisfied-feelin-lyrics.html
'Cause a smile upon my face is somethin' rare for them to see
But how can I tell someone else what I don't understand myself?