Years ago my Mom forbade me to answer the phone before I was fully awake. I would forget the call and often times I would come across as being rude.
Nowadays, it really depends upon how sleepy I am (and if I actually hear the phone). This morning the phone rang several times; I heard it but actually felt like not answering it (being way to early for my tastes). If it was important, the person calling would leave a message.
Not one person who called left a message.
Hmmmmmmmmmmmmmmmm …