By default, Ubuntu display a GRUB menu and give us ten (10) seconds waiting time for user interaction. If you feel this waiting time is disturbing, you can remove the waiting time by edit the GRUB menu. Set 'timeout' value to 0 (zero).
From Terminal, type:
sudo nano /boot/grub/menu.lst
Change timeout value.
And, do not forget to activate hiddenmenu option. Why? By activating the option, although the timeout is 0 second, we can enter to the GRUB menu by pressing ESC key.
Save the file!
