Key points of Buddhism

Four Noble Truths

In short: 

Noble Eightfold Path

Three Qualities (the eight aspects of the path can be grouped into three qualities as follows)

Three Jewels

Three Characteristics of Existence

Five Aggregates (skandhas)

Five Hindrances

Seven Factors of Enlightment

Four Boundless States

The boundless states or brahmaviharas are considered friends on the way to Nirvana. They help in dissolving the idea of a separate self.

In the below table, the "NearEnemy" is a quality that can masquerade as the original, but is not theoriginal. The Far Enemy is the clearly opposite quality.

Pali

English

Description

Near Enemy

Far Enemy or Antidote for

metta loving kindness good-will, friendship, unconditional love for all beings selfish love hatred
karuna compassion empathy to feel with someone instead of for someone pity cruelty
mudita sympathetic joy spontaneous joy in response to others success hypocrisy envy
upekkha equanimity even-mindedness based on insight into the nature of things indifference anxiety

Ten Fetters of Existence