If so, are some people evil?
Is a bad action evil, or just a mistake, or an opinion of the action made from regret or self-crticism?
‘Bad’ actions are those labelled as such, and are also called mistakes or sin (Sin meaning “missing the archer’s mark”) Bad or good are comparative terms. For example, while most agree murder is bad, it is common dress up the murder of others under the label of ‘war’ or ‘capital punishment’. We change the labels to suit how we see things. Typically, humans externalize mistakes or responsibility, either in the form of blame of a system or evil persona, or in the form of rescue, in the form of salvation.
Salvation, the need to be saved from bad behavior, assumes that not being saved will be dreadful, worse than the alternative. Some religions believe that your bad decisions or behavior, or even thoughts, will result in eternal, unremitting pain and punishment. (e.g. the major Abrahamic religions, Christianity and Islam, that the majority of the world population adhere to, accept this eternal punishment is possible in the afterlife – in a state of suffering called Hell, Hades or Gehenna.)
Punishment and suffering, both, are ways of interpreting reality. Each person will define sin or evil depending on their own experience, filtered by their own way of seeing things. For example, one person may see a violent death as the worst kind of suffering, another may see the same death as a heroic act of courage, and die happily, as many martyrs have done.
Interpretation and comparison of suffering depends on the extent of self-blame, which in turn depends on the belief system of the individual. If a person identifies an act as consistent with their moral code, chances are they will be happy with the act.