The 10-year test
When I was about 20 years old, I missed my grandfather's funeral.
I remember justifying not going because I was extremely busy with college activities, and attending his funeral would've meant having to travel from Washington, D.C. back home to Montgomery, AL over a couple of busy school days.
So I opted not to go.
Thinking back, I can't for the life of me remember what occurred over those two school days while my entire family was down at the funeral. But I'm sure the memory of attending the funeral would've been mine forever.
Nowadays, if I have the option to attend a meaningful life event, and I try to convince myself that I'm too busy to go, I counter it by asking myself the following question: if I don't go, will I remember whatever I did instead 10 years from now?
If the answer is "no" (which it usually is), the choice becomes pretty easy to make.