Popper proposed that a scientific theory must be falsifiable: it must be possible, in principle, to show it false. The same test works for any note. "Coffee is overrated" survives every observation, so no source can support or refute it. "Most adults in this survey reported drinking coffee daily" names something a source either shows or doesn't. Before writing a note, ask what finding would make you take it down. If nothing would, you've written an opinion.