Sikhism teaches that self-centredness (Haumai) is the main cause of evil. Haumai has five basic elements:
prideFeeling pleasure in your own achievements.
lustHaving a strong sexual desire for someone.
greedHaving an intense, often selfish, desire for something, eg money.
egoA person's sense of pride or self esteem.
angerBeing strongly annoyed with or hostile to someone or something.
The belief is that serving these five elements cause Sikhs to become separate from God. This in turn, causes suffering.
Many Sikhs believe that human beings are designed to be able to control and use these emotions. These emotions are important for us in order to live happy and fulfilling lives, eg without lust there would not be any children.