Passé composé vs Imparfait

That's a good question. It has to do with verbs of state (les verbes d'état) which usually go with the imparfait, since they describe a more timeless state of being rather than an action. Here is more on them on kwiziq: https://french.kwiziq.com/questions/view/what-are-verbes-d-etat-s-il-vous-plait

A more complete list can be found on the internet if you use google.