I think one key desire here is the ability to do a sprint of good productive work but still be motivated to maintain the road dial rate thereafter.
The way that I like to do this is by watching the yellow guide lines above the road which run parallel to the yellow brick road. I try to never drop below the highest line I’ve reached. If I do go below it, I’ve got some work to do to get on the right side of my new (high score) road. If you use this idea then Beeminder never has to lie to you about safety buffer but you always know whether you’re resting on your laurels and using up your buffer.
Beeminder could make this more natural by making the top guide line that you’ve reached a different colour or pattern. This is the feature that I would most like to see for Beeminder.
If you’ve been awesome in the past and had to use up safety buffer because of other priorities then the waterline of your previous best might be too high to be motivating or meaningful. This is easily addressed by using the point with the largest distance from the YBR in the last fortnight (or any time period).
Heck, let’s go feature crazy here. Let’s make the datapoint GOLD (or black! or pink!) if you check in with your goal today above your current waterline. And tomorrow, you’ll be black again provided you do more than your daily quota. If you’re only green you’ve got more work to do!
This solution addresses the boringness of watching the safe days increase. Everyday it lets you skate the edge of your own awesomeness and make it even more awesome. And I’ve seen it work for my brain.