Difference between selfless and selfish

Well it can be argued that all acts are selfish in nature.

We give to another for a personal reason after all.
"I donate to others because it makes them better off, in which makes me feel better about myself".

I am not saying selfishness is inherently a positive or negative, but something that motivates us to ultimately "accomplish" anything.

To that extent, I would say selflessness is, more or less, a identification as to what type of selfishness they possess, one that achieves at the expense of others, or one who wants to live in a type of balance. This is how I see it at this point.

Everything you do has something to do with the self in one form or another. Some people may think your helping someone as a "selfless" or "good" deed but you could just be doing it to impress others or to make you feel good about yourself. Doing something that absolutely does not involve you in any way does not seem possible because humans have ulterior motives even if they are subliminal. Those who's desires lie outside of assisting others would be called selfish because they don't wish to be involved with others, but all humans are selfish in their own ways. If you tell me that what you do is for the benefit of other people and not your own "gain" (context) then you're just lying to yourself.

I regard selfishness and selflessness as two different things because of the impact they have. Selfishness tends to only benefit one person and it had negative outcomes for others while selflessness ususly benefits others greater then the one preforming the act.

Selfishness is doing something for yourself because you want to. For example, say you want to get something, but you told someone else that you would get them something. Selfishness would be making an excuse to not get something for the other person simply because you want what you see despite the fact that it wouldn't leave you with enough money for the other person. Even if it's a super cheap copy of *insert rare thing here*, it's still selfish.

Selflessness, on the other hand, is doing something that you don't need to, but do it anyway despite getting either no additional reward compared to what you normally would have gotten, or less of a reward instead of making someone else do it. For example, say there's an empty role in a team. Now, that spot is very vital to the success of the team, but it's also the hardest spot. Regardless of whether or not you like that job, selflessness would be giving up what you're currently assigned to instead take that role that nobody else wants and expecting no additional reward. Maybe you actually like that role, but giving up what you wanted to do for that role is selflessness.

Some people get a sick, twisted, sadistic pleasure from being selfless, but I don't believe that matters. So long as the person does something they don't have to and expects little to no reward (or turns a reward down), it's selflessness. Accepting a reward isn't selfish, but it's not selfless either.

Selflessness is doing something for the good of others despite there being no reward, or benefit for the person doing it.
My example of this would be Dark Souls. (Spoiling one of the endings of the game, sorry).

THAT is being selfless.

Selfish is doing something to benefit yourself despite the misfortune, or suffering of others.

Well you said there are no differences in the two concepts when that in itself is incorrect. The concepts of the two words can be summed up in a couple of definitions

Selflessness-Having, exhibiting, or motivated by no concern for oneself; unselfish
Selfishness-stinginess resulting from a concern for your own welfare and a disregard of others.

This ^

I don't see the two being the same at all.

Agreed. I try my best to a truly selfless person at heart. And let me tell you, it's not a easy job for a human. If I was a machine then it would be easy, but being a human. It's very difficult to do because your own limits.

Yeah I completely agree. It is difficult, but as long as you try and do your best, than you should feel good :3.

I believe that selfishness is doing things that you want to do at some or much expense to other people, or doing irresponsible things that will affect others because you want to do them.

Selflessness, on the other hand, is when you give up parts of yourself, or do services for others, or just help others in general, expecting nothing in return, and even when offered something in return, you turn it down, and you could even say something like, 'pass along the torch, do something nice for someone else,' or, 'I did it to help others, not myself,', etc.