If you don’t stay on top of things you’ll find your profits begin to tank when your rides break down, your paths are covered in trash, and your staff has all quit. As you add attractions to your park more people will begin to attend, earning more money but also causing a spike in the things you have to keep track of.
You have to make sure to put plenty of stalls for people to buy food, drinks, and souvenirs, that there are enough bathrooms and trash cans, ensure the park is adequately staffed - it’s actually a lot of responsibility. This not only includes managing the building of rides but also all of the other park operations that come with it.
The concept behind Roller Coaster Tycoon is simple: you are in charge of a theme park.