There are plenty of factors that would make living in post-apo world a nightmare that are not reflected in the game. Modern humans are not fit to live in a world like that, there is no healthcare and doctors are scarce, infections and diseases would be spreading quickly, a simple flu would be life threatening.
Denutrition would be a problem, lack of food, water, vitamins. Pests and rodents everywhere, no access to fresh water, keeping hygiene extremely hard. Gangs, thugs, wild animals, cold, heat, parasites.
Modern lifestyle can be stressful, but its really nothing in comparison. Not to mention you can greatly reduce the stress you have to deal with in your real life by adjusting your attitude, life goals and choices.