Being positive

So here's what I've gotten done today so far.
-Mowed the front and side lawns
-Worked with M. on creating and planting a flowerbed
-Watched a movie with the kids (City of Ember) so we can take it back to the library; discussed how the movie compares to the book
-Washed the dishes
-Cleaned the bathroom floor for the first time in I'm-not-going-to-tell-you-how-long
-Washed, dried, and put away a couple of loads of laundry
-Made banana-chocolate smoothies for the kids and me

And here's what I haven't gotten done today so far.
-(Insert list here of 9,827 things that really need to get done soon)

Why is it so hard to focus on what has gotten done and so easy to focus on all the things that haven't gotten done? Looking at the first list, I think it's been a pretty good day. But I can't help thinking about all the other things I wanted to accomplish. I need to figure out how to be productive and positive at the same time. Any advice?

Why do I...

...not think to replace worn-out things? We have a set of clear, hard plastic "glasses" we've been drinking out of for probably 8 years now. They're so scratched and scuffed up it's hard to tell whether they're even clean. Today I was at the store and the idea occurred to me for the first time, "I could get some new ones!" I bought 6. It cost me about $4. The old ones are in the trash can now. For some reason I never thought of this solution before. Frugality is great, but this was just silly.