Check out the above photo that my cousin just took in San Francisco (Game 7 NLCS vs. the Cardinals). I just posted it on my Instagram to show an example. The black bars above look horrible, yet you still see a lot of people who decide to post their photos this way. They do not want to force crop their photo into a square, so they leave the bars. Yet their photo, no matter how beautiful it may be, is ruined by the black bars.
Use Squaready to turn the black bars into white, or “invisible”. Photos immediately look much better against the white background of Instagram: