A three year old boy was in the store a while back, playing at the train table while his mom was shopping. He was concentrating on the trains intently, as trains are apparently Serious Business. In fact, he didn't seem to notice a beautiful two year old girl arrive at the store.
The little girl sidled up to the boy and stared at him for a while. As he continued moving his train he bumped into her and instinctively started pushing her out of the way so his train could proceed. She responded by picking up a train car and offering it to him. While he took the car without looking at her and attached it to the end of his train, he continued pushing her out of the way.
Their game continued for a while: she, offering him train cars and getting in the way; he, ignoring her advances and pushing her aside with his forearm. Meanwhile, her mother finished shopping, praised the two for playing so nicely together, but said that it was time to go. The little girl smiled at the boy, announced "I love you!" and kissed his cheek.
In response, the boy unceremoniously raised his forearm in defense.