There is no good reason not to be grateful, because the truth is, our happiness in life depends upon the attitudes we espouse. Once we recognize that we are the captains of our vessels, we also understand that no one else has the power or ability to ruin our day, unless of course, we give that power to them.
Others have tried to ruin my day before- they tried to sour my attitudes, my outlooks, my hopes, and my ambitions, and I let them.
Consequently, over the course of many bad days, I finally came to realize that my awful feelings were not a result of my actions, but of my reactions to those actions. In other words, I let others allow me to make my own days miserable.
It was not that the day was bad, or even that those individuals made the day bad, it was me. I let their words and actions affect the peace and serenity within me. So, as soon as I understood this truth, I deviced ways to avoid letting others determine my attitudes in life. You too can!