Unsolicited advice/interventions
You can really save someone a lot of time, effort, or pain. Or help them improve.
OTOH, sometimes you ARE wrong, unsolicited advice does not always come across well, and... well, you probably gave them advice because you care about them, but also, being the guy who always knows better (whether true or not, rarely matters) does not help your relationship.
I think giving advice only if asked, and otherwise, rewarding good behavior is A solution. But for example non-alcoholist me thinks I would prefer people to take a more interventionist approach, if I were to regularly take drinking to an excess.
A good first step isn't to give advice but to start asking questions about the issue and listen empathically.
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