Okay kiddo, have you ever seen a big house with a lot of rooms and fancy decorations that looks like it belongs to a king or queen? Well, sometimes people want to have a big house like that too, but they don't want to spend as much money as a king or queen would. So, they build a house that looks big and fancy, but isn't as well made as a real palace.
These houses are called "McMansions". The "Mc" part of the word means they are kind of like fast food - they are made quickly and cheaply, just like a burger you might get at a fast food restaurant. Sometimes, the people who build these houses just want to show off to their friends and neighbors that they have a big, fancy house. Other times, they think that having a big house will make them happy or successful.
But, some people don't like McMansions because they can look weird and out of place in a neighborhood with smaller, more traditional houses. Plus, they aren't always built with high-quality materials or careful planning, so they might not last as long or be as comfortable to live in as a well-made house.
So, it's important to remember that having a big house isn't the only way to be happy or successful, and that building a house should be done carefully and with good planning so that it will last a long time and be a comfortable place to live.