I was browsing today through the news on kde.org site and I found the KDE-CVS-Digest (something similar to a report of the recent activities - for the ones who don’t understand).
One thing that really impressed me was a recent optimization that claims to remove flickering and make Konqueror (the file browser in KDE) load directories 2 to 3 times faster. That is something most of the KDE users noticed. Too many redraws makes your computer look slower.

I think this kind of “discoveries” is the reason why I like the OpenSource communities. There’s always somebody who finds/implements something and makes everybody else’s life a lot easier. Everything is so dynamic (some of the people might say too dynamic)and such optimizations make you really enjoy each and every contribution.