Milton's God is by far the least charming and least interesting character in all of Paradise Lost. His reputation since the publication of the poem has not been good. In fact, one critic (William Empson) once compared Milton's God to Joseph Stalin – you know that Russian leader who starved millions of people to death? Even though Empson was a cranky British man, he did have a point: Milton's God isn't really the most sympathetic character. He doesn't make us feel warm and fuzzy in the way that most father figures (like your grandpa or Santa Claus) do. In fact, it's just the opposite. For many (including Empson) he causes feelings of revulsion and anger; God's clearly not the people's champion. Geez, we can't even see God because he's just like a cloud of light or something, always shrouded in mystery, as if he's too stubborn to show himself (it's not really clear, however, that he has anything to show other than a bunch of light).
OK, fair enough. But let's pump the brakes here for a minute. God is God in this poem; He's not human, and he's not angelic, so we can't really expect him to act like a person or an angel. He's an eternal, spiritual deity who can basically do anything and know anything. You don't really want him to have lots of emotions to act on do you? Yeah, sure he could be a bit nicer, but he doesn't think like people do. Yeah, we get that he does lots of things out of love (like create the world) but it seems to be a different kind of love, one that is more spiritual/logical and less human – i.e., not the kind of stuff for Valentine's Day cards. Raphael suggests something to this effect in Book 8 when he says to Adam: "Be strong, live happy, and love, but first of all/ Him whom to love is to obey, and keep/ His great command" (633-635). Our friendly angel suggests that loving God involves obeying God, or rather God's definition of love involves some notion of following the rules. Like we said, not stuff you think about when it comes to Valentine's Day.
People always feel sorry for Adam and Eve, and they should. But, at the same time, Milton's God isn't necessarily unfair. He makes his rules clear to everyone (to Adam and Eve, to Satan), and he makes the consequences of disobedience clear as well. In fact, God's rules are pretty reasonable. For Adam and Eve it consists of a single prohibition; for Satan it's a bit more complicated but still relatively simple (some respect, some praying, and an acceptance of God's Son as the deputy in charge). So, to complain about God's arbitrary power and tyrant-like ways (like Satan does throughout) or to blame God for Adam and Eve's suffering (like many a reader has done) seems silly: Adam, Eve, and Satan all had the opportunity to live in the greatest places ever (Heaven and the Garden of Eden) and blew it. God is pretty fair, even generous, when it comes to that. He just wants a little respect and obedience in return. He does, after all, want things to be somewhat meaningful; in other words, he wants Adam and Eve to choose not to eat from the tree out of love for him, and he wants his angels to respect his Son and thank him regularly. Is that too much to ask?