I agree with sssstew, it's all in the context. The first one I can imagine being used in the context of some car related task, IE 'that was an **** of a job'. The second is a little more difficult to imagine.
The ones I find entertaining are the double meaning ones. For example, there is one company/brand that has it's name censored, but their name can also be used in a normal sentence without referencing the company.