Everyone has a bad day. 
It isn't something you can always stay away from. If everyday was a good day, life would get boring! 
Part of the way we learn is to make mistakes and to try to avoid repeating them. Bad days are just part of the experience of learning. When we see a homeless person smiling, we often wonder, how can they be happy? 
After all, they have no place to call their own, they have no work, no obvious way to get food and medical care. What is it that makes them smile? 
The answers may surprise you; For many, the smallest gesture or thought can become the most wonderful feeling.
A small thing like a coin to buy a coffee can turn into the most important part of your day.
A cheerful 'Hello or Good Morning' may be words to be appreciated. 
A simple 'How are you?' may be interpreted to 'At least someone noticed me today!'
When you have to sleep on the street or park bench, or go to the soup kitchen for a meal, it can be deadly on your dignity. 
To lose everything but the clothes on your back will make you feel severely depressed. 
When a complete stranger takes a moment to recognize and acknowledge you as a member of humanity, this can turn your bad day into a day to be celebrated. 
Remember, bad days are part of what makes you human. You get smarter and stronger with each experience. 
Take your bad day and wear it proudly, we all have them.
The most important thing is to use that experience to grow, tomorrow could be the best day you ever had!