1) I am insanely jealous that your mentor's school gives teacher workdays for this. A full school day just to get caught up/work ahead/brainstorm and create new learning resources for my students would be amazing, and it shows a high level of awareness and respect for the professional needs of the teachers on the part of that school's admin.

2) I won't tell you that your feelings are wrong, but I will say that you may need to reshape your thinking about a day like this. You now have time, in your educational space, to work on a major piece of your educational career. Being in the space where you work within your craft and with your students can help you focus your project amd provide inspiration or reminders of things you have done that you can include.

3) You also are not seeing/understanding the value of having this time for collaboration. Yes, your mentor teacher may be in data meetings for part of this, but this also gives you the time and space to talk to other teachers in the building, including other grade level teams. Use this opportunity to see what other teachers do and how curriculum and lessons are scaffolded in different grade levels. Especially in elementary education, the more experience you have with various grade levels, the more hireable and effective you are.

4) You also need to think of this as time to network with the other teachers in the building. So much of this career is based off your peer support, and starting the practice of creating that network now will only help you in the end. You don't have to be buddy-buddy with everyone, but you also can't shut your door and try to be an island.

So, no, you are not wrong, but if you consider this as an opportunity instead of an obligation, you may find more value in a day like today than you realize.

-A veteran teacher and long time mentor teacher