If a person commits idolatry or fornication he is sinful. Not only that, but the curse of Hashem is with that person. On the other hand, if a person does a lot of mitswots (commandments) and believes in Hashem and lives by his torah then Hashem is happy with that person!
So does this mean that humans have an effect on the mood of God because we can make him angry if we don't do what he commanded us and we can make him happy with doing what he commanded us to do? Can you please clarify?
In the Moreh Nevuchim, Rambam explains how God's attributes should be understood without compromising God's unchangingness.
He compares God's mood to a fire. If you put ice in a fire, it melts, then evaporates. If you put clay in a fire, it hardens. If you put wood in a fire it burns... The fire causes many different and contrasting effects without changing the fire's properties. The same "fire melts certain things and makes others hard, it boils and burns, it bleaches and blackens." It is the properties of each individual material that elicit a different interactions with fire.
Similarly, our actions change properties within ourselves, and it's those changes that elicit different interactions from God, without God changing.
Additionally, Rambam explains that God's "jealousy and wrath, kindle His fire and anger" are reactions solely elicited by idolatry. By worshiping idols, one makes them-self an enemy and adversary of God.
I don't think "happy" is a word we can use to describe God, it's a human/time-related state of mind. If you follow God's commandments though, He will turn His face to you - meaning Hashem will pay specific attention to you, and watch out for you.
God is beyond time and he cannot change or be affected by our actions. Whenever the Torah describes an emotion of God, there is always an action that takes place in this world with it. So a person may sin, "God gets angry at the person", and the person is punished. The meaning of God's anger can be understood as the punishment the person received. God still has will for this world, but He does not have time-bound "emotions" in response to people's actions. See the Moreh Nevuchim for further discussion of this topic.
