A belief is —for practical purposes— something that we thought is true. The incredulity or disbelief is a case of belief where we thought of a belief to be false. To doubt about something means to keep the related true-false judgment in suspended or pending state. To ignore is to have a complete absence of that judgment. To know something or to acquire knowledge is the outcome of a process that serves as basis for a special belief, one that is properly justified.
A religious belief is part of just one more type of belief within the extensive spectrum of belief types any given person could uphold. In current sociology of software development, many people uphold beliefs very similar in nature as religious beliefs, e.g., "X will remove all our problems" or "This important project will succeed because we have adopted X"; where X is any fashionable trend or buzzword blindly followed.
Most of the time, the conduct of a person can be explained in terms of the beliefs this person upholds in the occurrence context of the behavior in question. The context can include social aspects like office, school, home, church, etc. Our beliefs have great power to influence our behavior and while our beliefs remain our behavior will do so.
The correlation between the chosen conduct and its consequences (costs and benefits) encompasses the fuel that feeds the process to improve our beliefs, and therefore, our behavior. This correlation is not the only input for an improvement process, it is only one that is usually more affordable in comparison with other inputs as can be a tragic or catastrophic personal experience, also it can be the increase in conscience because of the understanding of a justified true belief about the same subject matter.
A key question is then: Which process have you chosen for the improvement of your beliefs?