I liked the whole movie (tampon in a teacup had me rolling) but I just didnt understand the ending.

SPOILER (but then if you read the title of this post you prolly knew I would spoil it, and eff it if you havent seen it yet i should have the write to spoil it.)
Ok, so that old man waits for years to catch a bus, but then she gets there and waits for a couple of minutes and it shows up. What? someone please clue me in.