All Humans have this greedy, selfish and jealous in them, it takes self control, maturity and commitment to limit it from affecting us.
Everyone have what makes them foolish and greedy for, so keep this mind when you meet people and they are acting selfish.
That is why it is advisable to always be around people who shares the same interest with you, to avoid being around too many selfish and greedy people (as you may think) who are chasing their self-interest.