The Good Humor truck and its music, searching or begging for a nickel, the sound of bare feet or flip flops slapping across the sidewalk! Good times in SoCal!
We also had the Helms bakery truck, @Epigonos I always wanted a cream puff! We also had a local vegetable truck too.
One childhood home I lived in had milk (eggs/OJ/more) delivery from Adohr farms. The milkman would come right into our unlocked home, a polite knock on the door and he’d call out “Adohr!” And proceed to the fridge(s) and stock them up. Even ice cream sometimes - held with dry ice in his truck.