When we see others make mistakes, do not judge and do not punish them. What you perceived as a mistake may not be their mistake after all. Instead it may be your mistake. Your misjudgment. A famous story called the 'Cookie Thief' explains this scenario very well. A lady who was so engrossed in her book, thought that the man sitting besides her were eating her cookies that she had just bought earlier. She thought the man was irritating. She didn't realized her mistake until she got into the plane and found her bag of cookies in her baggage. The moral of the story here is not to rush into judgement, for you might feel ashamed of yourself when you find out the truth.
Human make mistakes. Do not laugh at them, do not hate them and do not tease them for their mistakes. Seek for the truth. If it is the truth, then be a human friend who understands that human do make mistakes. Help them out in a loving and friendly manner. Forgive them. Learn from their mistakes.
Do not judge others from their physical appearance, their behavior or their reactions, because we do not know what is in their heart. Let God deal with them because He knows what we don't. Instead, judge ourself, "Are we better than we used to be?". Every day is a chance to be a better person than we used to be. So grab the opportunities. Focus on yourself before you focus on someone else.