Another thing I hate about the Prius.

I suppose that makes three things now.   The third one is that the displayed MPG calculation is always an overestimate.   It seems to be something like 2-5% over.   I can understand it might be difficult to make an accurate estimate, so I am not complaining about the error rate.  I am complaining that it is always an overestimate.   It should be sometimes optimistic and sometimes pessimistic, and then over the lifetime it would be more accurate.

Also, the only option for mpg display is essentially a tank indicator.  All cars should, imho, have a lifetime indicator and a trip indicator of mpg, trip being since you switched the car on I suppose.    A tank measure would be neat but less important.