Maybe I got the term wrong by user interface I mean the graphics and the arrangement of icons.
As per the example below.
I find the various buttons and graphics more pleasing, don't you?
Discussion
Hum.. they are def a lot bigger, bolder, softer and occupy more screen space. We always tried to keep them small because: 1. The post is the important part, not the reactions and 2. Lots of screens are really small and bigger buttons tend to get more on the way of content.