It's difficult to go through your life and forget to go to work. You have a job to do so that you can make it through life. The bible is filled with verses that warn against not working and being lazy. Do you know what your job is as a citizen of Heaven if you are saved? You are an ambassador! It is your job to get as many people to become citizens as you can before you are called home. How have you been doing at your job?
The days of Noah were some really bad days. The Earth was populated with 10 generations of men, from Adam to Noah (Noah being the 10th generation from Adam). The average natural lifespan of these generations was 900 years - many generations overlapped previous generations. Each man had many sons and daughters throughout their lifetimes, so there were many, many people populating the Earth.