Yodo YOLO Shirt
Only once, you live, young padawan. Then you can become a Jedi ghost if you are strong in the Force.
Yoda knows what is up. Hell, the dude lived over 800 years, so he was able to perfect his art. You'd be really good at something too if you had that long to work on it.
But maybe Yoda really sucked for his first couple hundred years. Like he was a bad student and all the other Jedi picked on him for looking so weird and sucking at the Force. He could well have been the dunce of the Jedi academy. Then in mid-life, around year 450, it all started to click for him.
Whatever the case, Yoda knows some stuff about life and he kicks the knowledge. So when he says, you only live once .... er ... as he would say it, "Only once you live", you know you should heed his word, get out there and started doing what you want to do in this life!