1. People in the congregation will not be aware that you are doing your job when you do it well.  "Well done" says the person to the worship leader.  But not so with the sound mixer.  Take silence as a compliment.

2. People in the congregation will be aware of you when ANYTHING related to the sound system goes wrong (or if you mess up)...and you'll catch a bit of grief for it.  "No more sleeping in the sound booth," you hear.  Learn to accept it and not internalize it.

3. You will typically hear only two comment; too loud, not loud enough.  While you could tune it out, ask a few questions like, "where were you sitting" and "what part was too loud."  While many times it's just one person's personal preference, it could be due to a speaker problem or something you overlooked during the service.  When you want to know how it sounded, ask fellow sound operators or church leaders - the people that know and the people in control.