Two.

My father made one unspeakably huge mistake in his life. I hate saying or actually writing it. He talks about it almost every time I see him; he always tells me to not fall into the same abyss. I won't make the same mistake, I won't let myself...because if I do, it will forever compromise my happiness.

He tells me there are two decisions in life that matter, one more than the other. I will keep them to myself, guess if you want.