When you suddenly realize the
meaning or
derivation of words you've been saying all along without questioning them. Sometimes it can be shocking, sometimes it's just cool.
The only one i can think of now is when i realized that the opposite of
inept is
adept (i'd been trying to invent the word
ept and realized i didn't need it).
(later) Oh, wait, here's another: I became briefly
enchanted with the word
indeed when i split it into its
component parts.