It can definitely be normal, and we had a lot of conversations like Portia's. I'd caution that if it persists or starts to include any verbiage specific to someone else or sound depressed to talk to a mental health professional. In our family's case, there was something unfortunate afoot that needed attention, not just garden variety curiosity. (Not to scare you...the population incidence of the underlying issue was less than 0.1%.)

What is to give light must endure burning.