I refer to those particular stats as the male nipples of the dashboard. Mostly just for show, very few people know what to do with them, most forget they even exist.
In terms of work that you can do, there are really only 2 stats that have a noteworthy impact
-Total HITs approved
-Approval rating
I'd estimate that 90 percent of requesters who make the effort to customize their qualifications at all will be using one or both of those.
On the flip side, I've spent 6, almost 7 years on Mturk, and I can count the number of requesters who paid attention to your return/abandonment rate without taking my shoes off.
So...don't pick up HITs just to return them, obviously, but you'll be hard pressed to find any requesters who notice. The bigger concern is that returned HITs count against the number of HITs you can do in a single day. If you're the type of person who likes to max out, that might be annoying.