I really relish the book Please Understand Me by David Keirsey. Answering seventy questions will reveal what personality type you are. There being four main characters, Rationals, Idealists, Artisans and Guardians, with four characters within each main umbrella. So sixteen personalities in total. It's remarkably accurate, even in the most intimate of details.
Gaining an understanding of ourselves is very useful, I think, and can aid us in understanding others too.
For example, my mum and I can drive each other to distraction at times. To illustrate, imagine I'm planning a party for example. Initially, the idea is one big picture for me, with lots of ideas, thoughts and brain-storming.
My mum, on the other hand, is unbelievably detail oriented, flagging up negatives, even though the plan is still just at the birth stage. I'm not going to lie, it drives me mad!
Reading about mum's personality type though, makes me feel a whole lot less angst at such moments. What I tend to perceive as pessimism is merely a scout like need to be prepared for all eventualities. Mum's character tends to tackle the logistics as opposed to my idealist, 'any thing's possible', abstract take on things.
Knowing this helps me see things from mum's side of the room. It also shows that each personality adds value and a special something to every event, conundrum or task.