I'm a heavy rss user, mostly through Google Reader. I find reader a very easy tool to use.
But it's missing one function: an easier way to "Mark as Read" everything that is unread across all of my rss feeds. There is an option to Mark As Read for each rss feed, and its has some function: items older than a day, items older than a week, etc., although I think that's too coarse.
What would really help me after a weekend off the grid or a couple of days at the office when I've been deep in the weeds would be a function to let me Mark As Read everything, globally, in one action, with finer degrees of choice: 12 hours, 24, 48, 72, etc.
Or just let me clear out every single feed in one click, so I can start with a clean slate.
I understand that much of the joy of Google products is in their simplicity, and that trying to add "one more feature" leads you to monstrosities like Office, but these doesn't seem like a slide too far down the slippery slope.
Update: Reader Mark points out that I am one big pile of FAIL.
If one views their feed under the "All Items" view, one can then has the same Mark As Read options one has on the individual feed level.
I never had a reason to use the All Items view- that has big benefits. Hat Tip to Mark.