Your effect on others
Life is an interesting experience and we often don't take into account our effect on others based on what we say and do. As a physicist by training, I tend to see how science can help aid my points and the video below is one of the simplest examples I have seen that help bring this point home:
One small drop of water cascades across the surface of the water. Even more interesting is the fact that there is a drop that launches out of the water after the initial drop plunges below the surface.
Every thought, word or action impacts so many around you. Meg Wheatley released a book many years ago entitled "Leadership and the New Science" where she gave the example about butterfly wings in one part of the world affecting weather in another. This may seem like an extreme example, but I think the premise holds true.
You will never know how an action to help someone, a kind word, or a word of encouragement may make the difference for one who is struggling to succeed or just get through the day. I can remember many instances where someone came along side me and offered advice and encouragement that has made a life long difference. I have also had many who have thanked me for something I barely or don't even remember in the distant past.
Your actions make a difference. Plunge yourself into the pool and see how positively your entrance can impact and aid others who are all around you.
Likewise, take care in actions that could be construed as negative or destructive. These waves can have impact too and they may lead to perceptions that are based on intuitive thought versus data driven decisions. Kahneman's work on system 1 and system 2 thinking lend credence to the fact that often we make decisions that are based on observations or perceptions that are formed quickly without sufficient thought or data gathering.
When you choose to make an impact, think first about where the waves might go.