After having my Eris for a while now, I must admit, there is still a couple issues that bother me about it:
1. Press the "PHONE" button, and then you get a keyboard with the last 3 calls over top of it, and the "CALL" button bottom, center. Can't tell you how often, I've pressed one of the 3 people listed as soon as the app. opens, only to have it switch those names and I end up calling the wrong person.
REALLY pisses me off. I just have to train myself to wait for the screen to update after it opens BEFORE I try to press a name.
2. After a call is over, I go to press the "END CALL" button, only to have it change to the "CALL" button as I'm pushing it, and of course, that initiates a redial of the last call.

 

Unfortunately, these days, most people are more interested in the other features, and seem to forget the basic "phone" features.