What's one thing you always wanted to learn about computer programming but were afraid to? [on hold]

What's one thing you always wanted to learn about computer programming but
were afraid to? [on hold]

What's one thing you always wanted to learn about computer programming but
were afraid to?
Personally for me it's the floating point numbers. I get freaked out by
things like precision, rounding, representation, base, exponent, and all
the other floating point things. So I've never mastered it and I don't
even know what's the difference between float and double.