Sure, I try to greet everyone with a cheerful (or at least pleasant) "Good morning" every day. However, that is a practice that I have tried to follow since my first year as a teacher as a way of greeting my students. I find that doing so makes my own rough mornings more bearable.
Nor am I a fan of Mondays. A little over a decade ago, I'd wish people "Happy Fridays!" These were received with a more enthusiastic response than my "Good morning"s. When I moved to Skyview, I was asked why I didn't wish people "Happy Mondays!" My answer was to start doing exactly that. I have found that doing so lightens my Mondays (especially Monday mornings).
Hopefully, I'm lightening other people's mornings (and Mondays) as well.