Against All Nihilism and Antinatalism I don't think that life is good in itself. Life would be empty and horrible if we didn't actively try to make it good, or seek out good. I am a bit of a nihilist myself; i dont see the point in life as it is. Life has the possibility to be good, life is possibility. But in itself it is nothing unless something is made of it. Depression reverts one back to such state of nothingness, whether it is severe depression or not. Part of what makes life difficult is that it is endless possibility trapped in confinement; we dream freely but are frequently unable to fulfill such dreams- and when we cant reach those dreams, it feels empty.
I strongly think that the upsides do not outweigh the downsides..the downsides are usually the things that affect peoples lives the most; whether it be a trauma, a loss, anxiety, depression etc. People usually remember the bad instead of the good since it affects them more. I may be interpreting you wrong, but are you taking a bit of a hedonistic stance?