> My best rule for writing good subject lines is that they feel like they could be the subject lines of an internal email—this helps them feel natural in the in

> My best rule for writing good subject lines is that they feel like they could be the subject lines of an internal email—this helps them feel natural in the inbox. For example, “Quick question”, or “Idea for better outbound” are two casual, natural-feeling subject lines. This strategy has been in use for years and I perceive such subject lines as an indicator that an email is probably an outright scam. All senders receive a silent and permanent block from me without exception. Maybe the author isn't aware of how much alienation he's creating for his brand.