Spieel allows you to log how happy you feel in a particular moment in time, tag it, and then save an optional photo and diary entry with your entry.
Over time you can view you average levels of happiness over months, days and hours.
You can also filter your happiness log by tag, getting some deeper insights into how specific things or people affect your mood(pizza, that person, your job).
Being able to visually see how your levels of happiness vary over time would likely allow you to make some important life decisions with more clarity, or just allow you to fine-tune your life satisfaction a little bit more. Well, still use your judgement though - my logs so far reaveled that eating junk food makes me particularly happy, this is not something I think I should optimise for!
Privacy-wise, sensitive info like passwords and diary entries are hashed, and all network calls are sent over https and/or ssh. If you want to delete your account and associated data, you can do so instantly in the settings menu.
Spieel is only for android at this stage, if there's enough interest I'll port a verion to iOS too. I have some future updates planned, but will only look into those if there's enough interest.
Please be kind, it was only myself working on it on-and-off, early mornings and an hour here-and-there over weekends.
Hope this helps someone!
https://play.google.com/store/apps/details?id=com.spieel
Apologies, it's not available in all regions.