The best line I heard yesterday is: the sad, beautiful fact is that we are all going to miss almost everything.

When I was a teenager, some older ones urged me to experience life, "do whatever you can to enjoy it". After all, life is too short, having fun. The sad part is that, no matter what you have done, you will miss most things in life.

If this is the last day of my life, would I be satisfied? When I was dead, would someone claim that "without him, the human kind would take several more decades to get where we are now". The believers of historical inevitability would call me a liar, but one man's determination can make the difference. Half a century ago, one nation's determination stretched the ability of mankind to its extreme, and we sent a man to the moon 40 years long before every piece of the technology is ready (when the first commercial rocket reached the orbit).

If I, myself alone, can put a man to the Mars by 2030, that's all the difference.