1, different time points: going out to see happiness means going out to meet good luck, such as going out to find money or encountering good things. Opening the door to see happiness means opening the door to see good luck, such as visiting relatives and friends or receiving good news.
2, the scene is different: going out to see happiness refers to small luck in daily life, such as picking up money on the road, or buying discounted goods in the store. As soon as you open the door, you can see the blessings and gifts sent by relatives and friends on important occasions, such as weddings, birthdays, business opening and so on.