Gratitude is heightened by perspective. A couple perspectives which heighten for me are:
1) Being shocked I even exist at all.
What an unbelievable numerical improbability that you have a life to begin with. The chain of events for that to take place are absolutely unfathomable. Penn Jillette has a great musing on this subject:
""I don't know why you need more, you are the most amazing numerical aberration...the fact that you are here. The fact that you're living is astonishing...You've won the lottery. You won the biggest f**kin lottery that could ever be won in the universe."
That generates a feeling of just being astoundingly lucky to be living at all.
Richard Dawkins ha a great quote on this matter as well:
“We are going to die, and that makes us the lucky ones. Most people are never going to die because they are never going to be born. The potential people who could have been here in my place but who will in fact never see the light of day outnumber the sand grains of Arabia. Certainly those unborn ghosts include greater poets than Keats, scientists greater than Newton. We know this because the set of possible people allowed by our DNA so massively exceeds the set of actual people. In the teeth of these stupefying odds it is you and I, in our ordinariness, that are here. We privileged few, who won the lottery of birth against all odds, how dare we whine at our inevitable return to that prior state from which the vast majority have never stirred?”
2) Imagine a caveman time-traveled and woke up one day as you.
Through the eyes of a caveman who wakes up as you, he would be absolutely astonished and astounded beyond words. He'd marvel and be in complete wonder as to the technology and advancement the world had experienced. It would be as if he was transported to another realm, a paradise of sort, with a brilliance that his mind could never have even fathomed.
So it's really often a matter of perspective when it comes to life and being grateful and appreciative. And when it comes to small and mundane every-day annoyances which can set us off in a second, it's often helpful to remind ourselves, "If this is the worst problem in my life right now, I'm doing extremely well."