If we are returning tho the pre bubble era as I think we are, stocks can and will remain "undervalued" per the Fed model for long periods of time. That said 20% undervalued is a bit much and hard to lose going long at that level.
“The things that will destroy us are: politics without principle; pleasure without conscience; wealth without work; knowledge without character; business without morality; science without humanity; and worship without sacrifice.” Mahatma Gandhi