Sufyan ath-Thawree (may Allah have mercy on him) said that ten people are regarded as oppressors:
1) The person who prays for himself, but forgets his parents and other believers.
2) The person who does not recite at least a hundred verses of the Quran daily.
3) The person who leaves the Masjid without performing at least two units of Salah.
4) The person who passes a graveyard without greeting the deceased or praying for them.
5) The person who enters a city on Friday and leaves without performing the Friday prayer.
6) The man or woman in whose vicinity a learned person comes and none acquires any religious knowledge from him.
7) Those two people who love each other for the pleasure of Allah but are unaware of each others names.
8) The person who is invited by another, but does not accept his invitation (when acceptance does not contradict the Shariah).
9 )The youngster that has no commitments yet does not acquire any religious knowledge or manners.
10) The person who has eaten to his fill while his neighbor goes hungry