I know this is going to sound silly but I'm a bit picky and I couldn't help noticing how numbers in the activity widget were not right aligned and I feel that hurts my eyes :) So I ended up modifying that CSS so that they are right aligned.
This is before the change:
This is after:
I noticed most users here are not developers nor designers so if that is the case, and you happen to be as picky as me, then here is how to change it:
Open your qa-theme/<your-theme>/qa-theme.php file (note I'm using the Snow theme and this might be different for any other theme) and make sure these CSS classes (.qa-activity-count, .qa-activity-count-item and .qa-activity-count-data) look this way:
In green the lines that have been added. That's pretty much it.