They are all a waste of time.
"Well, let's say you can shave 10 seconds off of the boot time. Multiply that by five million users and thats 50 million seconds, every single day. Over a year, that's probably dozens of lifetimes. So if you make it boot ten seconds faster, you've saved a dozen lives. That's really worth it, don't you think?" [1]
[1]: https://www.folklore.org/StoryView.py?story=Saving_Lives.txt