If you take the rest of the Fruit of the Spirit and lay them out, Love, Joy, Peace, Patience, Kindness, Goodness, Faithfulness, Gentleness, there isn't really any ONE that stands out where if you're lacking it, someone might point it out. No one I've ever heard has said, "Look at that random person over there, he sure lacks peace in his life!"
But when someone lacks self-control, we notice it right away. In fact, lacking something like love for other people, or kindness might even get attributed (correctly) to a lack of self-control. Like most things in life, the world always is able to pick up on shortcomings rather than successes, so while most people will never be praised for their great self-control, several people will be criticized if they don't have it. It's definitely something to be worked on and honed as a skill.