Let's face it, we care what others think, and the expectations we have for ourselves (and for what others might think) can affect our play.
Many mental toughness books talk about our expectations and our "status". We instead should focus on playing the best to our ability and only concentrate and focus on our pre-shot routine, not thoughts unrelated to the very reason we play pool, which inhibit and paralyze our abilities. However, sometimes that is tough to do. But these two quotes are very helpful to counter that, imo:
I'll say it again:
"Winning or losing doesn't define me."
"What are you really scared of? Remember that no one crucial to your happiness is going to hurt or abandon you for winning or losing, for making a brilliant shot or a bad one.... "