I'm not religious, but the Bible does have some good advice about a lot of thing - I'm thinking specifically of Matthew 7 v1-3 here
1 Judge not, that ye be not judged.
2 For with what judgment ye judge, ye shall be judged: and with what measure ye mete, it shall be measured to you again. Mk. 4.24
3 And why beholdest thou the mote that is in thy brother's eye, but considerest not the beam that is in thine own eye?