If it is op spec and FAR legal, you go. If it is illegal or you are just to fatigue to fly another leg, you don't go. You have a mission to rescue someone's production program, that is why they call your company. It is about the job, and you find a way to get it done legally. You deal with, customs, haz mat, irate customers, TSA, loading facilities that tell you we don't load or unload, do it yourself. You refuse a haz mat load because the paper work is not correct, you get screamed at by the customer, the boss calls you in the office tells you the customer is irate and the company is going to investigate your behavior on the road. The company investigates, finds out you were correct in not taking the haz mat. No one pats on the back; you are in a hotel in LRD for the 5th night. You ensure the weight on the manifest matches the real weight, you find a way to get the cargo on the airplane when it doesn’t fit because of an error the salesperson made when the trip was booked. You pay for fuel, ensure its contract pricing, you walk ¼ across a snow-covered rate to pay a $5.00 landing fee, another ¼ in the other direction to pay a $400 loading fee when they did not help you load. You make sure you mark each receipt in letters a least ½ tall trip #, date, your name, airports name, contract and customers name. Then you get a call from the company wanting to know why you are not airborne. You are under a lot of pressure to get the job done. Those boxes have to be there by 0400Z to keep the assembly line running. If you can work under those conditions, on-demand cargo is not bad, it is interesting flying new places, with different approaches, and a changing adventure on each trip.