50 people, one question: What is your biggest regret?

Most people regret not having lived their life to the fullest or so they think. They might as well think so even if they lived an extra inch further, but how could they tell if this never happened in the first place? As for those with no regrets or funny answers, are they just running away from life and its meaning? Are they fully convinced? That's a very personal question and it's hard to tell if what is being said is heartfelt, acted or even staged.

What is your biggest regret?