Travel means different things for different people. For some, it's a way to explore new places and see new sights, for others it's more about taking a break from routine. Whatever travel means for you, it can be extremely annoying to say the least, when travel plans go wrong.
One cannot foresee and avoid contingencies. That's why they're known as contingencies. For example, if all UK flights are cancelled due to an emergency situation, there's nothing that you can do about it, no matter how well you've planned your holiday.
However, not every holiday plan gone wrong is due to an emergency. There can be many minor things that can go wrong. For example, rooms at a hotel could be double booked, which means there are more bookings than there are rooms. Or a rental car company could ignore the quote they initially gave you, and increase their price when you arrive!
To avoid such disasters, it is important to plan carefully and make bookings only with reliable providers. One way to find out how reliable a provider is, is to read reviews online and find any information that can tell you more about the performance and quality of a company such as car renting agency or hotel.
Planning a holiday can be fun, and thanks to the ease with which you can book things online, not very difficult either. However, getting a travel agent to plan a holiday is not a bad idea either. Agents often have local contacts and resources and information about good and reliable local companies.