Epicurus thought of justice as an agreement to prevent people harming and being harmed.

You can find many philosophy papers on the themes of 'love' and 'friendship,' most of which are cheerful and somewhat anodyne; you don't find many on the loss of friends, relatives, and lovers from death or alienation, though it happens all the time.

Outside of mathematics and logic, there are common sense truths, such as that it is snowing that normal observers, in a specified context can agree on, subject to vagueness considerations, and theoretical truths, such as that snow is crystallised water vapour, and maybe in-between truths.

Moral claims aren't, as a class, truth-value apt or not.

Epicurus was in favour of friendly sex but not of grand passions or marriage and children, viewing them as sources of trouble and vexation.

Epicurus thought of justice as an agreement to prevent people harming and being harmed.

Oddly, since by now I've written quite a lot on early modern philosophers, I didn't care for the history of philosophy, which I thought dull and obscure, until I got a minor job writing articles for a children's encyclopedia in the history of science and began to make connections between science and philosophy.