Thanks for the comment 😉
Honestly, I know both arguments, but actually, like it is in case of Sex At Dawn and Civilised To Death, there are a lot of misconceptions about the topic of happiness, and both statements you said fall in that category. For example, based on the work of Christopher Ryan, we know that we are not supposed to live like we currently do, meaning that parts of our unhappiness is caused by the way we are currently living. Now, my goal is not to create a debate here as we can make it here, buuuuuut:
1) Constant state of happiness is possible and it is not diminished by the the lack of unhappiness. Actually, prolonged unhappiness diminishes happiness
2) Idea of purpose (“knowing what we want,” as stated by Slavoj Zizek) also does not mean that we need to suffer. You can be happy and work on your goals. One does not exclude the other.