On the surface, the Songs of Innocence seem to be an exaltation of a naive, new, and vulnerable state of being. They indeed are. However, they can also be seen as subtly satirizing the dangers of an ignorant or one-dimensional state of being. In "The Chimney Sweeper," a pair of desolate children imagine being completely freed from physical existence into Heaven, ignoring their dire circumstances, in order to cope with life. We can imagine that Blake is suggesting and extolling escapism, or alternatively that he is making fun of escapism and ignorance. Most of the Innocence poems can be read in contradicting ways like this: celebrations of innocence, and subtle warnings against the dangers of total ignorance.
Songs of Experience arguably exhibits a far wider range of contradictions, and appears to be pointing out many of the contradictions Blake saw in Christianity in his day. In "Holy Thursday" and "The Chimney Sweeper," he skewers the hypocrisy of adults neglecting and abusing children. The parents in "The Chimney Sweeper" assume that because their child is innocent, the child is happy and the parents have done no wrong. While many of the Innocence poems hinted at exploitation, in Experience the exploitation is extremely overt. It contradict's the Songs of Innocence view of "innocence" as roughly equating to "happiness," by pointing out that children can seem joyous and innocent and still be suffering.
The poems emphasize the costs of ignoring poverty completely and setting your sights on heaven, as in "Holy Thursday," as well as the costs of repression overall. "The Clod and The Pebble" presents happiness as something that results from attempts to help others, and shows selfish happiness as a state of being that eventually results in despair. These poems show existence as more complex than in Innocence, and present a view of the world with more agency. Despite all of this despair, poems like "The Tyger" show the terrifying beauty that is not possible in the Innocence poems, suggesting that a life of agency is worth the costs; as well as that it is vital to fight ignorance whenever possible.