Interestingly this is why Quakers continued to address people as thou/thee long after everyone else abandoned the practice. Thou was originally the "informal" second person singular pronoun in English, "you" was plural. People used "thou" (the familiar form) in conversations with God. People used "you" as a singular pronoun to be polite. Eventually, "you" overtook thou.
But the Quakers believed that using "you" to show respect was anti-egalitarian and resisted the trend for a long time.
Nowadays because "thou" appears a lot in the King James Bible it tends to be associated with formal, archaic language, so if anything the connotation is the reverse.