The century is not so daunting if you take it easy and ride at a steady pace (unless its a climb-fest). I tend to crank it to 80% and try to go relatively fast (for me) so I push it hard. If I settle back to 60-70% effort like a long touring ride it would be a lot easier.

Some people think its just the fact of completing it that is the challenge, but its also how fast you are completing it.