You choose a time when you're already on campus to optimize your time without the burnout of a long day.
Unfortunately, the others in your program had the same idea.
Three of your office mates share the office space, leading to a loud and crowded office before class.
With all the noise its hard to get anything done and meetings run long.
However, if you're ever unsure how to answer a student's question you have an office full of peers to ask.