4 years for a U.S. presidential term. Older candidates wonder if they'll ever have another chance. 4 years between the Olympics. Older athletes wonder if they'll ever have another chance. 4 dots in the Star Wars ellipsis.... Except for Episode VI, WTH?? I wish I could have thought of a 4th thing.
Or you could add this to your list: The number four is considered bad luck in Japan; the Japanese word for "four" sounds like the word for "death".
Aw, man! I even knew that one, too! Some Japanese buildings don't have a fourth floor either (like the U.S. and the number 13).
I seriously thought I was the only person who knew/noticed this. If you check my posts going back to who knows when, any of them with ellipses have four dots.
I noticed it (or maybe just hadn't thought about it before) when I was making "opening crawl" style invitations for my son's SW birthday party.