Working a full-time job can be taxing, especially when most of your friends have part-time jobs that only require them to work a couple days per week. So then they're always making plans and your response is the same: "I'm working." And speaking as someone who technically works a 40 hour week but usually ends up working significantly more, I'm just as tired of saying that I'm working as you are of hearing it.
1. You don't really know what's going on in the outside world.
Your schedule is: Eat. Sleep. Work. Repeat.
2. Your days off are sacred and should not be messed with.
A day off does not mean a day to catch up on everything else you've been slacking off on, it means you don't want to get out of bed.
3. Tired is no longer a surprise, it's an integral part of who you are.
What is this "well-rested" thing people talk about?
4. You telling me I work a lot only makes me mad.
I KNOW I WORK A LOT.