This state of mind is called "ignorance is bliss." There's nothing wrong with it. Despite people thinking "happy" people have never had any hardship in life, it really just describes not wanting to explore what has caused them any trauma, thus, not letting those things affect them (in a negative way or positive way).

I've noticed this kind of person is usually the most uninteresting to talk to, though. But not everyone has to be interesting. In my experience, aside from their work, they seem to have surface-level conversations and interests and live a much simpler life. It's like an extreme form of pragmatism.

Also, to paraphrase Borges, happiness is its own justification.[1] In other words, it either needs no justification or, at the most, only a surface-level justification.

[1] "He sospechado alguna vez que la única cosa sin misterio es la felicidad, porque se justifica por sí sola."