The smarter they are, the more they observe and learn. This means they also learn bad or annoying things and it can be very difficult to then train them out of

The smarter they are, the more they observe and learn. This means they also learn bad or annoying things and it can be very difficult to then train them out of it. A good example is a border collie I know that accidentally broke a screen door, then suddenly learned that all screens can be opened at will and no window was safe. Smart breeds also need to be kept busy and entertained or they get anxious and angry. They'll start destroying property or fighting with others. If you don't have the time and energy, it's much better to get a less intelligent and mellow dog instead.