Apparently there is a common confusion, sometimes self-deception, about this difference. When people are working together, look at what it is that made them do it. Explore their motivations. They can vary a lot.
For example, when you look at a game like World of Warcraft, it’s one of the best examples for the worst kind of cooperation: Coerced by a ruleset, coercing loot-crazed egoists to participate in group activities because that’s the way to achieve their personal goals.
This kind of thing masks the real character of a person, and only when put to the test will it reveal itself.
Another type is like the above, but people putting up an act of altruism because they were subject to certain healthy social norms and don’t feel comfortable with themselves being an egoist unless they tell a better story of themselves.
This could lead to another phase where this self-lying is believed by the person themselves. (There’s a nice hint to that in Far Cry 2, or it’s literary source Heart of Darkness.) It’s like NLP, or self-indoctrination.
Then there are people who are not kidding themselves about their true egoistical motives and are OK with them. This is actually a step in the right direction. (Explaining why would require a lot more time. I’ll leave it for you to meditate on.)
All this will be very alienating to someone who is capable of real altruism, is doing sincere introspection habitually, is not just caring for themselves or for others only when it fits into their agenda, and is actually looking forward to enjoy seeing something accomplished, regardless of what’s in it for themselves.
Because it is a bit like this:
There is a game of everybody lying to themselves. It works as long as they all agree to keep playing by the rules. Only if someone introduces actual altruism into the game and the others realize it’s for real, they will fear that their game of deception might have to end. It’s like an insult to them, sometimes even the mere presence, because someone ‘thinks they’re better’ (They actually don’t, but the players ‘know’ (=believe) they’re worse and don’t like to be reminded of that). It’s an insecurity issue. Even if the altruist is understanding enough to not try and ruin their silly little game, it’s the nature of fear to always try to preserve itself.
That’s why it’s so important to sincerely hunt your fears, identify them, and then overcome them. One step at a time. Baby steps is much better than actively giving in to them out of convenience. The more people allow themselves that convenience, the more this burden will fall onto the very few who are too well-spirited to just stop caring and succumb. But, everybody has their breaking point, and they might eventually get majorly pissed and start gunning people down. And then, more than ever, having realized what the world has become, nobody wants to take responsibility, but instead revels in the dramatic rhetorical question “WHY?!” and their self-imposed convenient powerlessness. And those who do understand, but are naive enough to judge those people based on themselves and take it as a sincere question, will get demonized, making everything even worse.
And sometimes it seems things aren’t getting worse quick enough for people to get their shit together.
Someone whose personal aims are beneficial to yours is an ally.
A friend is someone who cares about you regardless of that.