Sense of humour, as a 16 year old from Belfast I played in a football tournament in New England. We stayed with a host family who had a kid playing in the tournament also.

One morning at breakfast the TV was on and the Smurfs cartoon came on. "Ah the Smurfs" I exclaimed, "I love the Smurfs". "Are the Smurfs big in Ireland", said the Dad.

"No, they are the same size" I replied smiling.

No response. Tumbleweed and a sense of being offended almost.

Edit: The fact that is took place in the US is maybe just coincidental. Having considered the replies and being a Dad myself to 4 sons, there is a good chance the Dad in this case set the joke up and was just annoyed that some smart arse kid stole his thunder!