The calories-in/calories-out philosophy for weight control is a scam.
There is no way that a person can live a normal life and accurately track the calories that are eaten to a precision necessary to not gain or lose weight. As Calianna showed in her post, it is very easy to over or under consume without no clue. By slightly overeating by only 25 calories a day will result in a weight gain of about 3 pounds a year.
The problem is even worse in trying to figure out the calories out component. It's impossible to track every movement and know how much energy the movements use.