People do not wear their pain on their sleeves. They tuck it into their pockets and although it isn't visible to an outsider, they are still burdened by it. So be kind. No matter what, be kind. Don't add to the weight people carry everyday. Instead, say something nice to them or wish them a good day or lend them a hand or just smile and acknowledge them as they pass by. Just be kind because you don't know the extent of the pain one carries, and even the smallest gesture of kindness can be a ray of light for someone having a bad day.