Some people think that happiness stems from achieving goals, like getting things or doing things, while other people think that it’s the pursuit, the attempt, at getting those things that provide happiness. This means that they think that should someone achieve their goals, like having a kid, getting a good job, or something like that, they won’t be as happy as they were when they were striving for those things.
I think that this is rather silly, and that it is the attainment of those goals that make people happy, not the attaining. I think that the reason many people who have attained their goals aren’t happy is that they had the wrong goals, or settled for less than they wanted, or just had bad goals, ones that would not help them in life. When they’ve achieved a goal, however, and aren’t happy, they’ll have no goal and become bored with their sad, stale life. when they are achieving a goal, however, they distract themselves from their sad boredom as well as growing closer to something they think will make them happy.
This distraction doesn’t lead to their being happy, it just distracts them enough to not realize how sad they are, and it’s always possible that they’ve hit upon a goal that will in fact make them happier, and so it’s possible they will become happier as they approach and hopefully achieve a good goal, such as raising a child to be proud of.