Offering feedback when others are generally unaware of the negative impact they are having can be tricky. When a trusted colleague or leader unknowingly becomes more negative, dominant, distracted, status-conscious, or disengaged (among other issues), we face a unique feedback challenge. How do we offer this feedback without creating a strong and negative reaction? The next time you confront this dilemma, think about suggesting to your colleague that they are “acting out of character.”
Messaging based on personal point of view works good here "Are you ok? You don't seem to be your normal <cheerful/optimistic/happy/content> self these days", "This isn't the level of performance I'm used to seeing from you." both send messages of confidence, concern, and caution.
Clever technique. Have you tried this with your significant other?