Hiring a car can be very easy but it all depends on the circumstances. It should be very easy for you to hire a car in the UK, especially as you will be given all of the paperwork to read over and check. This can all become more challenging if you hire a car in a foreign country. The paperwork may be in another language and the car company may be less reliable, trying to get more money out of tourists.
The most important thing to do is to make sure you have the correct insurance as this will protect you I the case of an emergency. Whether you write the car off or do a small amount of damage, the insurance you have will ensure you are protected and will not end up being out of pocket. Buy insurance online or from the rental car dealer depending on the requirements of the country you are in.