At a fundamental level, one aspect of happiness can be described as a feeling of relief or contentment. This suggests that happiness often accompanies or follows periods of challenge, effort, or even suffering.
So to feel happy, we sometimes need to, for example, set up constraints or make a sacrifice first. One cannot exist without the other; otherwise, it would even be difficult to differentiate between the two.
Realization of that has given me much more strength to overcome difficulties.