Very subjective lol
I consider myself to be an incredibly good, tolerant, patient and kind individual. When I see dead animals on the road, I mourn and place flowers on them. When I see snails or worms on the ground after rain, I pick them up and move them aside, all the while making sure I do not step on any. When someone asks for a hand, I give them an arm. When someone needs help and I am able to help them, I do what I can. Typically, when I'm being taken advantage of, I'm too naive to realize it, too lol
I think a good person is someone who always has the intention to do good for others / society as a whole and is rarely selfish, unless absolutely necessary.
An example from my own past regarding when being "selfish" is OK would be when I left my ex. He was incredibly angry, trying to contact me and harrassed me for not sending him photos post-break up/restraining order, but I put my own health and safety above his freeloading needs. I stayed with him and supported him, tried to get him to therapy and to take medication. I endured much over many years; however, one cannot say that in this kind of situation, my needs were not above his. My selfishness, in my opinion, was justifiable, and I can still be considered, by societal norms and ethics, a "good" person.
:)