Your milieu is not the same as your sister’s. It is an ever-shifting, individual configuration of information flows. The Twitter feed you have curated is a milieu. Your friend group (which is not the same as the friend groups of the other people in that group!) is a milieu.
It is by changing your milieu that you change yourself.
Conventional wisdom says "relationships matter most in life" and then conveniently leaves out that your relationship with yourself is the greatest predictor of your relationship with others.