if you think filling a simple form is "hassle", you don't know what the South American / Spanish system is.
In my country, to sell a car, both the buyer and seller must have a notary ("Escribano", a special kind of clerk with a graduate degree). The notaries must check several state and country records (with assorted fees), checking for mortgages, impounds, even parking or speeding tickets (across all 19 states, which have separate records and systems). Then they write a special contract, which has special legal validity since it was witnessed by a notary. That contract is entered into the country registry of property.
After all that, you have to pay your notary a hefty sum (3% of the properties' value for houses, and several hundred dollars for cars, even clunkers), both buyer and seller sign the contract, the notary witnesses the act, buyer gives the money to the seller and you're done.
So, after a few weeks, if all goes well, you can proceed to give the keys to the buyer :P
Edit: it's worse, here's another version (which skips several steps, but adds some I'd forgotten)
http://board.totaluruguay.com/Transportation/Purchasing_cars
"The usual order of events when buying a used car is...
1. Find the particular vehicle you want to buy either privately or from a dealer. The Sunday edition of El Pais offers a wide selection as does mercadolibre dot com dot uy and you already know about bottles. If you are used to northern second hand car prices, be prepared to pay an apparently eye-watering sum for an old car with an improbably high kilometer reading.
2. Find yourself an escribano/a to do the paperwork.
3. You and the vendor visit the escribano, present your IDs, sign the contract for sale, the purchaser pays the money, the vendor hands over a sheaf of papers and the escribano will provide the purchaser with the appropriate paperwork for the junta local to prepare a new "libretta" (plastic coated car registration card) with your name, your physical address and the car's details.
3. Before driving the car to the junta local, the purchaser will need to insure the car as insurance is now compulsory and the junta local will want to see a certificate of insurance.
4. On arrival at the junta local, the car will be physically inspected by a funcionario to ensure that the engine and chassis numbers on the vehicle match those on the paperwork. If the car lacks a current "patente" you will be charged for however many months are due for the remainder of the calendar year. If the vendor lived in the same departmento as the purchaser, the existing plates go with the vehicle. If you are re-registering the vehicle in a different departmento, you will be issued with new plates. It used to be the case that the cost of the patente varied from departmento to departmento. I have heard that patentes are to be standardised across the ROU from 2012.
5. The escribano will start a series of searches to ensure that there are no outstanding fines nor other charges due on the car in all 19 departmentos of the ROU. This process can take several months but you can continue to drive the car in the meantime. You cannot take the car out of the ROU until this paperwork has been completed as one of the documents will be a certificate from the Ministry of Culture confirming that the former owner(s) were not Uruguayo figures of cultural importance. :-) "
That's why my country has the dubious distinction of being "most bureaucratic country on earth" for several kinds of stuff (car transfers being one, and construction being another, being so bizarre as you having to have a permit and pay taxes to paint your own home)