Looking to rephrase something for my son.

Hi all. I typically greet my 14 yr old son when he gets home from school. Usually something like "Hey! How was your day?" and "Did you have a good day?" or "How did everything go today?". I just want him to know that I care about his day and to give him an opportunity to share if he'd like to. (Ex: This teacher drove me crazy... I'm being bullied... I met a girl... whatever. I just want to keep the dialog open.)

I've noticed for a long time though that he seems to feel irritated by these questions, so today I asked him why. He basically said "School is school" and that he is just annoyed that I ask him the same question every day. That wasn't my intent at all.

Is there a better way to let him know that I am interested in his day and to help him feel more comfortable sharing the little things about his day? After what he said today, I feel that I need to phrase things differently. Thanks!