Why they like food in restaurants?

A Chinese couple like to eat out everyday in restaurants. Sometimes, they come to this one. They will order four or five dishes- even for three persons(they have a toddler), that's a lot. But the wife is a big person and she likes to eat more than her husband, I blieve. She has two big moles on her face--one at the beginning of the left eyebrow and another at the end of it. They are so big that everytime I look at her, I am attracted by the moles. So lets call her "Mrs. Mole".
Mr. Mole is a good husband. When the baby started to kick or cry, he will hug him and walk outside on the street to make the baby happy while Mrs. Mole is goggling at the table.
Another time, I saw Mrs. Mole walked on the street and her husband followed her one meter behind, with the baby in his arms. They like to change restaurants everyday. The restaurants are their kitchen. When getting bored in one, they try another one.
But they never cook food for themselves.
I cannot understand why people would like do that. Of course, when I was working, I'd like to go out with my colleagues or friends occasionally or maybe every noon. But I will still leave some time to prepare food by myself. If you eat out every meal, what will you do if you want to celebrate something? Another concern is that the food from restaurants not always as clean as they look.
The forks, plates and cups are washed by a man you will never have the chance to meet. They hide at the back of the kitchen and do all kinds of dirty jobs there. With a good chance, he may be a Mexican who never takes medical examination. He may get bored to wash dishes everyday and wash them in a careless way--just imagine how hard it is for you to wash your own plates cleanly. Therefore, some dirt or detergent may stay.The process to make a dish is so complex that any step may go wrong without noticed. The raw material may be put in the same cart that you ever throw your plates in after meals. The food may be fried in dirty oil. The cook may tasted or touched the food. The food may fell on the ground, be picked up to the plate and sent to the table. Even worse, they may not use a board to cut food. They may directly cut it on the table where they put dirty dishes.
The possibility to get diseases from restaurants is higher if you go to them too often. You can never trust those out-sourcings if you know exactly how they works.