Every action I take affects the whole, due to the thoughts I hold, or my physical presence, anywhere at any time. Say I'm walking through a grocery store. Nobody knows who I am, right? I pick up this item and then that, maneuvering my way past other shoppers, lingering at the muffin display, standing in line at the checkout, leaving the store. An absolutely mundane series of events yet the way I interacted with the people in that store made an imprint on the whole, to the tiniest degree. I had a particular effect on things and so do you when you shop. Energy, voice, gestures, etc., all of it makes up Presence and the other people in the store take note, even if it's only through a passing glance or an overheard exchange.

Maybe they might not even look at you at all but- your energy contributes to the overall fabric and this isn't some New Agey airy fairy talk, this is everyday reality. We as humans constantly employ our senses in every interaction by default. I can't turn my sight off, my hearing, or my sense of smell and I also can't shut off the energy I'm emanating, which might more commonly be known as my 'vibe'. You may not believe in the last one, but it's there. Check it out next time you're in a store. 'Energy' might cause you to linger in Aisle 3 or avoid the person in Aisle 4 or it might make you want to rush out of the store due to the turbulence you feel or you might be intrigued, repelled, or indifferent about the person(s) in front of you in the checkout line and it's not entirely due to the clothes they are wearing, the style of their hair, or the perfection/dimensions of their physique. 
    The grocery store experience is a microcosm in the macro world of experience and you are a butterfly having an effect so you might as well be a good butterfly because, well, why not? What kind of grocery store experience do you want to contribute to, now or in the future? A junior high school cafeteria, high school field trip, frat house, stock trading pit, street brawl, or block party shopping experience? (I’ve been in many of the street brawl ones, they are not enjoyable).
We demonstrate who we are by how we act, how we think, what we think about, and how we move. Like it or not, earth life is a movie set, a fashion catwalk, a defendant in front of the jury, a wedding walk down the aisle, a group around a conference table, a solitary figure under a spotlight, spectators in a crowd. Until you're not here, you're ON, making an impact, greater or lesser, leaving a trail of encounters (and memories) in your wake wher'er you go.