It takes a certain kind of self-discipline, a certain mindset to not get angry or frustrated by situations that have gone wrong, but are entirely outside of your control.
This is exemplified by traffic. People who get angry in traffic do not have this particular zen. But it's also a useful skill to have when
- someone has a family emergency and has to cancel on you
- a restaurant loses your reservation and doesn't have any tables to accommodate you
- UPS fails to deliver a package you stayed home from work all day to get
- The dry cleaners don't get your suit jacket back in time before a big trip
Something about letting go in those situations seems antithetical to human instincts, but it's a skill worth cultivating.