Amazing Spider-Man #248 was written by Roger Stern with art by Ron Frenz and came out in 1984. It opens simply:
After proving that he is in fact Spider-Man (by lifting the kids bed over his head), Spider-Man and young Tim have a conversation. Spider-Man tells him how he got his powers (radioactive spider bite), that he was motivated to fight crime because he let down a loved one (Uncle Ben), how his webbing works (wrist mounted shooters), and that he has a Spidey Sense. They share some laughs about J Jonah Jameson and then Spider-Man prepares to leave:
It's just a small moment: no supervillains, no worlds to be saved. Just a little boy who needs a hero. And that's: Why I Love Comics.