Play hard and seriously, but:
For most of us, this is a social game where the object is to participate and be competitive. Keep it simple and friendly, but know and play by the rules.
If you don’t clearly see a ball as out, it is in and should be played. The call belongs to the side where the ball is “out.” Exception: You may call one of your own shots “out.” You may not call one of your shots “in” if the other side feels it is “out.”
Let your partner play also, but be sure the “line of doubt” is covered! Both excessive “ poaching” (for “social pickleball”) and not playing proper position are “unfair” to your partner. Learn and play proper positioning.