I find this to be very true. I have actually done a lot of work on this myself. Now if I find myself getting annoyed by something I try and take it as an opportunity to look inwards. And also understand that everyone else is dealing with things that we know nothing about.
A book that I always come back to, that really helped me with this is 'Loving What Is' by Byron Katie. It really helped to change my perspective on a lot of things. But also to just let things go more easily. I am far happier as a result.
Also journaling has been instrumental in helping me deal with things that are rumbling through my mind too.