Well, anything that relies on goods/services in the real world is going to be difficult by virtue of the fact that nodes aren't able to determine whether a good

Well, anything that relies on goods/services in the real world is going to be difficult by virtue of the fact that nodes aren't able to determine whether a good/service was really delivered. You could, however, get a rudimentary employment contract by keeping payments in an escrow account until the end of the month (or your employment is terminated early). This would prevent wage theft by the employer while also allowing an employee not to get paid for not doing their job, though it couldn't handle more complex clauses like penalizing violation of an NDA. However, there are plenty of cases where the employment contract can consist of creating a digital object that solves a problem in NP (for instance, code that passes a randomized test suite), in which case the employment contract can exist completely on the blockchain.