If you want to raise the happiest child ever there are some things that you can say that can make them feel glad. In fact they will remember these kind words forever. In essence, anything that an adult tells a kid can affect him or her forever.
You want to raise your kids to be self-confident, responsible and caring. However you need to think twice before criticizing anyone, but especially children. If you put things the wrong way you will put things in his or her mind that has them develop rebellious attitudes.
If a child asks you why something is so, one of the worst things you can do is say 'because I say so.' Do not answer 'Because I am the dad/mom and not you.' This tells the kid that his curiosity or feelings don't matter. This creates a secretive kid that does not trust authority and that does not tell you anything. Nobody likes to be patronized in this way and it turns your kid into a rebel. They will be silently plotting their separation from you because they will see you as uncaring and controlling.
One of the worst things you can do is act like you are too busy to pay attention to what the kid are trying to communicate. This makes a kid feel unworthy. You need to reassure the kid that you will have time later if you cannot address their issues in the moment. The happiest kids are the ones that always know that their family is always going to be there no matter what.
You should also not criticize a kid if they do not do something well. Not every kid is good at sports or can play the piano. You need to focus on what the kid can do rather than what they can't do. This is because the kid things that you are only focusing on his or her incapabilities and nothing else. You need to focus on the kid's successes and constantly point them out.
Making your kid happy is all about making his or her self-image blossom. Every single time they leave, kiss him or her goodbye and every time they return welcome them home with joy and genuine acceptance.
Remember that kids develop their entire psychology based on their momentary emotions. They are profoundly affected by the things that happen to them and their reactions to what you say to them!