正常的挫败感

Scalar variables in Perl are always referenced with the leading $. In the shell, you use $ to get the value, but leave the $ off to assign a new value. In awk or C, you leave the $ off entirely. If you bounce back and forth a lot, you'll find yourself typing the wrong things occasionally. This is expected.

这段话引自Learning Perl第三版 2.5 Scalar Variables。我就遇到过这种情况，当时非常具有挫败感，一种暗无天日、没有前途的感觉。看了这段话，心理舒服多了，正常嘛，大家都这样，并非我个人的问题。

就我看来，This is expected这句话的价值非常大，它让人不必在无谓（或者无法控制）的事情上浪费感情。