There are scenes in American movies where a person receives a present, quickly rips off the wrapping and uncovers the present. Even a present nicely wrapped in beautiful Christmas wrapping paper is roughly ripped off. Many Japanese viewing the scene cannot help but feel chagrin at such beautiful paper being roughly treated.
In Japan, there exists a unique sense of the artistic in wrapping paper such as origami, noshibukuro (an envelope for a gift of money), and the furoshiki (a wrapping cloth), although people using the furoshiki have now become fewer in number. The Japanese feel a certain resistance in roughly ripping off the wrapping from a present in front of the giver who took special care in bringing the present especially for the occasion.
People from other countries who shop at department stores in Japan are impressed by how carefully their purchases are wrapped in beautiful paper, an indication of how highly the Japanese regard wrapping to be.
However, the main reason seems to lie with the inability of the Japanese to outwardly show their feelings. Although they are genuinely glad, they are embarrassed to show their feelings in front of others. This makes them unable to open a present in the presence of the giver.