Building Moodful: what should a mood tracker do to actually stick?

I’m building Moodful (https://moodful.ca) because I wanted a simple way to answer a question that’s surprisingly hard: what in my life actually correlates with my mood being higher or lower?

A lot of mood trackers fail (for me) for predictable reasons:

• too much friction per day
• too many fields / too “clinical”
• no easy way to look back and spot patterns
• you stop for a week and the streak shame kills the habit
So we’re trying to keep Moodful deliberately lightweight:

• quick daily mood score (1–10)
• optional notes + tags (sleep / exercise / stress / social / caffeine etc.)
• trends over time
• export

Question for IH: what are the 1–2 features (or UX choices) that make a tracker stick for you as a daily habit?
Examples: streaks vs “no shame” mode, reminders, weekly review prompts, correlations, templates, integrations, etc.

If anyone’s willing, I’d love feedback from real usage—happy to incorporate suggestions and report back with what we learn.