A few days ago I got annoyed by OpenOffice starting slow. Then I decided to switch to LibreOffice and first thought it helped. Then a day after it was slow again.
Finally I found out that it starts slow whenever I have the VPN connection open (using SonicWall NetExtender).
After searching the internet a lot without finding anything that helped I landed at LinuxQuestions at this thread: http://www.linuxquestions.org/questions/linux-software-2/double-clicking-on-open-office-files-leads-to-very-slow-opening-808048/
sudo tcpdump -nnl -i any -s 1536 dst port 53
on the commandline discovered that LibreOffice was searching for
So similar to what is mentioned in the thread above, I had to add
to the file /etc/hosts - done. This and some other small, but annoying changes in reality need to be done at each install of a new system. - Of course, there are even more of those annoyances on Windows, but it seems you can't get rid completely of those... :-(
Related posts: Ubuntu 10.04 & docking station part 1 + part 2, Locale configuration on Ubuntu, Firefox change default page format.