Perhaps we can separate any expectations of how things will divide between Optimistim and Pessimism once Peak Oil bites into three subcategories of things which can be expected to react:
1. How will individuals react and feel ?
2. What about various special interest groups ?
3. What about Countries ?
In Summary:
Optimistic for People, Pessimistic for existing power structures
In a bit more detail (aka minor rant) :
1. Individuals
I suspect it will depend on each person's specific circumstances, whether they can still feed themselves, avoid worsening debt (and consequent loss of freedom), maintain their friendships... These are things which Epicurus tells us are ultimately important, or should be, to individuals.
Except where densely packed or unable to farm, oh dear for Cities and Suburbs

, individuals and communities should be OK or at least able to adapt.
2. Special Interest Groups
They will probably try to maintain cohesion, e.g Corporate entities to continue trading, political entities to maintain influence.
The SIGs will cause hassle for individuals. E.g. Banks attempting to foreclose on loans... but SIGs should just be ignored if they compromise your happiness ! Bullies
3. Countries
Here is a big problem. The Government and related politicians will want to maintain their system of control

. They won't really be able to... after all, if money can't buy you food but helping out with a community harvest can get you and yours fed then why bother with money any more.
If individuals stop caring about money then top-down Govt. is in big trouble.
I suspect that many Individuals and Communities can cope with a great deal and remain optimistic. Pessimistic individuals will be those whose world-view is shattered, so EDUCATE people, people!
SIGs will be pessimistic, and rightly so... If the pyramids of power are thrown up and land in a different arrangement they're all history.
Countries, well the people who run them, are probably not so much pessimistic as paranoid about losing power. Still that's why they like telling us all what to do and think so often and loudly ! We can safely ignore them, it's better than reacting to them... Think of it as ignoring a fractious child and only rewarding it with attention when it talks slowly, calmly and without trying to annoy everyone.