Well, let's see...
"Rainy Day People", taught me, at that vulnerable awkward, age how to be a friend and what qualities to look for in a friend. I guess that would be part of the coming of age process.
"If You Could Read My Mind" helped me through my first heartbreak. "Talking In Your Sleep" helped me recognize the impending second one. "Dreamland" allowed me to be strong and say "no" when he wanted to come back. I don't know if young love/heartbreak can be considered an "occasion" - but it sure felt like one at the time
While it certainly didn't happen/hasn't happened in my life, "Go My Way" would be a perfect engagement song and "Beautiful" would would make for a heartfelt anniversary sentiment.
Just a few to throw in the mix-
Janice