What are the things that you can't leave home without?

These are the routine things we can not leave without at home. I think every body has his own priorities to complete before leaving the home for a travel or routine to office or at work. The most thing I do not forget is my office key,my lunch box and m water for the day which I carry with me to my office. There were two three times when I forget to put the bag carrying Tiffi n and water bottle. I had to return half way to collect.