I think that not only online, but also in real life, we show people only the side of us that we want them to see. It may be easier to hide some things online, where we don't interact as much with people, but no one else knows all of us as well as we do.
Also, while reading about acting like our better selves, it got me thinking... if we act like our better selves all the time, we eventually become our better selves, right?