情侣挑战互相买手机壳，坚持用一周不换，没有丢人只有胜负欲！

Group 1 - The article discusses a challenge between couples where they buy phone cases for each other and use them for a week without changing, emphasizing the competitive spirit rather than embarrassment [1] - The challenge highlights the playful nature of relationships and the desire to win in a lighthearted context [1] - The focus is on the fun aspect of the challenge, showcasing how couples can engage in activities that strengthen their bond [1]