It is, amusingly, one of my comfort rewatch movies. I liked this quote from Sondheim about his aborted interest in making it into a musical (which Tim Minchin did eventually).
"I'm not the first person who's thought of it. Many have. But, I feel to make a musical of Groundhog Day would be to gild the lily. It cannot be improved; it's perfect the way it is. I don't want to touch it, because it's perfect. Pretentious as that sounds."