I've read reviews of George Friedman's book about the next 100 years being a American Century, an Optimistic take no doubt. I suggest reading it(though I haven't) along side Walter Russell Meads "God and Gold" which is an excellent history book, if looking to find some ryhme to the reason.
that said, there are things that concern me but I try to remind myself I should have a Long View that is Optimistic, but that doesn't necessarily mean that in the short-term things can't become very bleak.
Starting with Demographics, in the West vs. Islamic countries
Then Postmodern Philosophy(
)
slides toward Socialism..
Corrupt Church(see Tillers for example, PCUSA, most Episcoplian...)
Another "Dark Ages" period is possible IMO, but on the other hand people have been calling for Doomsday forever and things keep getting better gradually.