Regrets of the dying
I wish that I had let myself be happier.
This is a surprisingly common one. Many did not realise until the end that happiness is a choice. They had stayed stuck in old patterns and habits. The so-called 'comfort' of familiarity overflowed into their emotions, as well as their physical lives. Fear of change had them pretending to others, and to their selves, that they were content. When deep within, they longed to laugh properly and have silliness in their life again.
Confessions from the deathbeds, in the most literal sense.
While it all sounds very poignant and resonating, let's not forget that being in a terminal situation DOES introduce a reality distortion. Some choices will appear easier when we no longer have a real chance to make them.
