The observer effect is a theory in physics which states that when we actually try to observe a particle, like an electron, its behaviour changes because of the act of observation. It states that presence of the observer changes the observed.
While this theory has been indefinite in regards to evidences, this paints a hue of truth in our lives. We change our behaviour and actions depending on who we think sees and surrounds us. Sometimes, who we are when alone is very different from who we are when surrounded with people. But we should always remember that the actions that we make should not be based on people looking at us. The reality is, our actions are judged, not by the external appearance, but from the motive which dictated them. If our motive is so to please men, and the action that we have done is only prompted by a selfish heart wanting to receive applause, it is not acceptable to God. Paul says, For do I now persuade men, or God? or do I seek to please men? for if I yet pleased men, I should not be the servant of Christ. Gal 1:10
However, if God is the observer that we want to please and it is the consciousness of His presence that prompts us to do our actions faithfully, then the observer effect becomes a positive thing. The actions that we make become pure for it comes from a heart filled with a love for a Saviour and a wanting to give Him the glory alone.