Get ready for the best piece of advice I could give to anyone. The most important lesson I've ever learned is that gratitude should always be your number 1 focus. Here's why...
You'll be happier
Newsflash... happiness is not a destination. You can't book a flight to happiness and spend the weekend. If you want to be happy you need to be happy that you even get to focus on your happiness. You need to be GRATEFUL that you get to work towards a goal. You need to be GRATEFUL for all of the experiences, materialistic things, and lessons you have had throughout your life because they were blessings. Whenever I get pissed about something not going my way I look back to who I was in 4th grade... if I had no experiences I would still be that person and there is no way in hell I would rather hang out with my 4th grade self than the woman I am now. I'm thankful that I've had and will have the opportunity to grow. So now when something shitty happens in my life I can look at it as a lesson and say thank you to the universe for helping me grow. I have nothing to be sad about when I look at life that way leaving only room for happiness.
You'll be more successful
Because guess what? You're going to be grateful for your day and actually use all of it to its full potential. You're going to be grateful for any handouts, advice, help, or advantages that come your way and you're going to use them to help yourself be more successful. You're also going to be grateful that you received so much help and give back when you have the means, which builds you an army of loyal followers instead of enemies you stomped on to get where you are. You're going to be grateful for your success, you're going to thank the universe (or God or whatever you want to call it) and in return for your gratitude it'll supply you with more (I mean look at Oprah she can't give money away as fast as she earns it, but the flow of energy keeps in coming in).
You'll have healthier relationships
I'm not a relationship expert, but I do know that if someone does something for you and you don't say thank you, resentment will build and it'll leave a crack in your foundation. I literally say thank you for every single thing like letting me eat your leftovers or even just hanging out with me. I've never met anyone who ever said "I don't want to hang out with so-and-so because they're just so grateful for everything I do for them". I have, on the other hand, heard the opposite on multiple occasions. The more gratitude I get for doing things for other people the more things I want to do for them. I mean just be grateful that they're even in your life and watch how the relationship builds. BTW this includes romantic, familial, and platonic relationships.
you should be grateful regardless because if you're not you look like an asshole to anyone who has less than you do. Go stand in front of the kids living in landfills in Brazil and talk to them about how rough your life is because you got a speeding ticket WHILE SPEEDING. You're problems are only problems because that's what you've labeled them. I call them lessons or maybe even inconveniences, but my problems are not problems compared to 99% of the problems everyone else in the world has. Show some respect.