Here's a super-secret hint to make today a good day: Smile.
Look around as you go about your day. Notice how many folks don't look like they are having a good day.
Catch their eye and give them a sincere (not crazy) smile. There's a good chance they'll smile back and they'll hold on to that smile for a bit. It's likely you will too.
Here's another exercise, while you are doing this or that, smile. You can be smiling all alone or in a group but, if you take a moment to remind yourself that you are where you are supposed to be, doing what you are supposed to do, you will be making today a good day.
A smile is a cheap, easy way to show that you are having a good day. Give it a try.