One of the 40Nawawi ahadith focuses on giving naseeha (sincere advice) but we often forget the etiquite of giving advice and think ourselves "heros" who go around correcting people's mistakes in the name of advice.

The Prophet (PBUH) said, "Facilitate things to people (concerning religious matters), and do not make it hard for them and give them good tidings and do not make them run away (from Islam)."