imitating the kuffaar

Q: Celebrating birthdays is permissible or impermissible in Islam?

Q: Is it permissible for women to wear skirts and tops at home?

Q: What does emulating the kuffaar mean? Is it only confined to clothing or does it also relate to other aspects of one's life? We see the kuffaar driving cars and eating and drinking in plates and cups and we Muslims also do the same. Is this not also emulating the kuffaar in our actions?