That's how it is at age 9; jokes must be processed.
Sometimes it's easy. For example, the old poem ...
I eat my peas with honey,
I've done it all my life.
It makes the peas taste funny,
But it keeps them on my knife.
... was probably safe to scorn. But a thicker joke must be laughed at since you don't want to be branded as an unworldly boy who doesn't understand fully what the word "know" means in the Bible.
I myself didn't fully understand the Italians/mechanics joke until I reached the age of 19, when I bought my first Fiat.
The fact that I have to say "first" will give me away as a slow learner.
It was a canary yellow 124 Sport, and it would go around curves fast enough to knock your radio out of tune. At least it did until the rear sway bar failed, which mine did magnificently on W.Va. 9 between Berkeley Springs and Martinsburg, when we were playing the game of "15."
This is where you try to go 15 miles per hour above those yellow "Maximum Safe Speed" signs that show a characterization of a car spinning out of control and going over a cliff in flames. For the record, DO NOT try this. You may get away with it three times out of four, but there is always that one sign with the typo, which --never mind. Just trust me, I know.
Back then, the driving age was 15 and the drinking age was a floating derivative based loosely around a combination of your actual age and whether the owner of the convenience store knew your parents. You also had to be smart about it. You couldn't just walk in and ask for a sixpack of Gennesee Cream Ale and a pack of bubble gum with a Frank Robinson rookie card.
Remember, I grew up in Berkeley Springs, so a Frank Robinson rookie card would have only been making it to our neck of the woods in the early '70s. It was like Mark Twain said of Cincinnati -- that's where he wanted to be when the apocalypse hit, since it would happen about six months later there.
I've never been to Cincinnati, so I can't say whether that's true, but I was bicycling through the Midwest once when a kid in Illinois asked me how much they were paying me to ride a bike across the country. So the concept of tourism had clearly not arrived in that neck of the woods.
Of course in that part of Illinois we were riding through there wasn't all that much to see. So one night when it was getting dark and four of us were still about 30 miles from our destination we felt no remorse about hitching a ride with a guy in a van who was pretty much bored with sitting in a strip-mall parking lot, but didn't have a lot of more encouraging prospects on the horizon.
Which, in a curious way, brings me back to the joke. I say "curious," because in the beginning I really had a point to make about it, but now I've forgotten what that point was, and here we are. I guess the lesson is that old age is a horrible thing.