mainly because travelling dont just fill your passports with stamps but because its a great way to be one with the world, to learn new things (not all stuffs are being learned at school) to have new experiences, to learn a lot of lessons, to know different stories of different individuals and places, to open our minds of whats really out there. Some people dont understand the feeling we get when we travel, its the feeling of peace and contentment and the feeling of being free excites us thats making us do it more. Travelling might be pricey but some people works hard now in order to travel soon and to experience what i stated.