Never judge anyone.

There was once an old man, that sat at the same park bench day after day. A younger gentleman that went running in this same park almost daily always saw this happy, smiling old man, and always wondered why he would just come to the park, sit and smile. Finally after about a year, his curiosity got the best of him, and he stopped to ask the older gentleman why exactly he sits in the same spot daily and just smiles at everyone who passes by. 
The older gentleman replied "When my wife was alive, she used to walk laps around this park, while I used to sit here and read and watch her pass me. I can't help but to wonder, if in some way, since she loved this place so much, that I can maybe get a glance of who she was somehow by just sitting here and doing the same thing I used to do when she was alive." 
You never know what someone is going through, and you never know how you can help someone if you just don't judge them before knowing who they really are!