Discuss, think and learn with a friendlier atmosphere. Avoid tangential, meta, indirect, personal or harsh criticism.
In Friendly, posters choose what topics they want to discuss. Suppose someone posts a physics question. Don’t reply about how their question reveals that they’re dishonest, emotional or overreaching. Don’t criticize them for ending the discussion early or for not doing Paths Forward. Those would be topic changes away from their intended topic (physics). If you do want replies like that, put your topic in Unbounded.
Challenging, questioning and disagreeing with people is OK, but don’t subtly or indirectly undermine people. Don’t be passive-aggressive. Don’t hint at people being wrong or bad, while maintaining plausible deniability about whether or not you’re criticizing or attacking them. Don’t imply criticism without saying it openly or directly.
Project planning discussion is allowed even if it could be taken as implied criticism of poor or non-existent project planning. You can ask about someone’s goals, plans, backup plans, resource budgeting, prerequisites, topic prioritization, project scope, what they want from others, what they are offering to others, how and why they chose this project over alternatives, whether or why they expect to succeed, etc. Try to be helpful instead of attacking people. If someone doesn’t reply, stop. People can opt out by silence or by saying they don’t want to discuss project planning. If in doubt, ask “Is project planning discussion welcome?”, and treat no response as “no”.
Any thoughtful topics can be fine except politics. Good topics include: philosophy, rationality, learning, thinking methodology, discussion organization, morality, memes, science, history, writing, grammar, math, evolution, programming, statistics, economics, political philosophy, psychology, psychiatry, parenting, education, relationships, atheism, skepticism, business, sales, marketing, art, design, social dynamics, culture, and decisions people face in their lives.
News can only be shared in Friendly if you focus more on philosophy than on the news. E.g. focus on critical thinking, analysis, or trying to deal with it rationally. Your post should be more timeless than time-sensitive. And avoid political controversies in Friendly.