I wouldn't say it's bad. If you've always had a healthy diet and find yourself at a healthy weight and in good shape, you don't need to worry about counting calories, just stick to your healthy lifestyle and you're fine.
If someone wants to lose weight, it's a good idea to get into the habit of counting calories. It helps when you know exactly how much fuel you're putting in the gas tank, in a manner of speaking. If you want to clean up your diet or lose some weight, it's good to count calories so you get a good sense of how much calories are in different foods. You'll be shocked at just how high in calories some types of foods are - things like fast food and snacks which are very high in sugar and fat. Once you see how unhealthy they are, you might want to avoid such foods and switch to healthy foods which are not too high in calories while still being quite filling. For people who eat a lot of fast food, sugary snacks and sugary drinks, all that sugar can potentially add up to a huge amount of calories.