Not so much old, but I was having a discussion with a friend the other day, and we were talking about one of the unfortunate things about being an adult is that when you're more "knowledgable" about certain things, your adult mind can easily misinterpret something that was meant to be totally innocent from a kid's perspective.
Case in point: on another forum, a younger member started up a thread with the title "(Character) and (Character) in Bed." Seeing that thread title, my mind immediately assumed this was going to be some Rule34-esque fan art of the two characters engaging in some rather inappropriate activities, then to turn out the OP was sharing a photo he took of plushies he has of the characters in his bed.
I've found as I continue to get older, I have more and more moments like this, where my adult mind is quick to misinterpret something that was intended to be totally innocent. Very ironic too, considering once upon a time, I was in their position: I was young, innocent, naive, didn't know about the facts of life, and there were times I'd say or do something innocent, and older kids would interpret them as something completely different, then tease me for not understanding what they interpreted to be something dirty and full of innuendo. On the one hand, part of me misses having the mind of a child; when you have the mind of an adult, it's easy to make innocent things seem dirty, whether you do is consciously or not; on the other hand, part of me also wishes that I knew certain things then that I do now, and I probably could have avoided some embarrassing situations and reduced the amount of teasing I endured for having a sheltered mind as a kid.