Life is very short if you live it the traditional way. By the time you realize what is what (or, what you came here to learn in this life) it feels like there is little time left to enjoy it.
But a lot of this comes down to self-awareness and whether or not it interests you. There are many actively religious places on this Earth (India, Nepal, Bali(!)) who will happily laugh at you for saying we live only once.
And as for me. I distinctly remember when I was five years old, I used to think we could only have one life and my parents used to think that way too. And then you wake up to the reality and you realize that life isn’t finite. But imagine if it was? How different would the experience be on this planet?