After impersonal expressions that indicate a willing, wish, command, preference, desire, necessity, opinion, etc. on the part of the speaker that another person do (or not do) something, the subjunctive is used in the dependent clause, after the word que:
 

However, if the expression does not reflect the desire to influence a specific person to do something, but instead is a statement that people in general should do something, then the infinitive (-ar, -er, -ir forms), and not the subjunctive, is used.