if the disease was someone that you cared about, then go and pay last respect. Also, like you said, it will make you look at things in different perspectives.
as for wedding, if that is someone close to you, then try to go, not everybody marries that many times, for this person, maybe this is the only time.
for schoolmates get together, that is something that you may skip. YOu can try to catch up at a later time. But funeral and wedding, for the "main character", when the show is over, it is over for good.
