I usually ask the person if they would like me to open it up now? of course, they always say yes! But I think it's polite to ask. When I give someone a gift, I like to see them open it. I would be really disappointed if they set it aside to open later, like maybe they think it's not worth opening, or that they might be disappointed so they're waiting till I'm not around. So I'm glad that you posted this, because now I can think it's just a cultural thing - why they don't open the gift. I won't feel bad anymore!