"Everyone's feeling a bit summery this morning, with a few rays breaking out over Britain and some of you lot daring to break the 'anyone who wears sunglasses in April is a prat' rule that we just made up." – 3am.co.uk, April 6, 2011
This is a common and useful expression in spoken English. It also describes a certain type of stubborn personality. It’s not really a good quality, but it’s a character trait that many people have.
This is a great phrase to explain a certain type of negative psychology. If someone “takes themselves too seriously” it means they aren’t seeing the humor with what they are doing.