I bet you're thinking that this is a post about germs and all the bacteria you find at the water cooler? Well, it's not. It's easier, in a way, to fight the germs because your body does that automatically. You don't have to think about anything. Your body operates in its own best interest.
Compare that to your subconscious mind which operates automatically but that operation is based on what we have stuffed into it all our lives - and worse yet, the things that others have stuffed into it (parents, media, clergy, friends, etc). Your subconscious doesn't know anything about best interest or not best interest. It just "is".
What happens when people gather together at work? They talk. About what? About lots of things. Often it's about family and kids and that might be really cute stories or it might be complaining about what little Joey did at school yesterday. Or they might be complaining about work and what's wrong. Or even better, talking about (complaining) what's going on in the world or the country and how it "should" be fixed.
Even if you just stand or sit there and don't participate in the talk, you're absorbing the momentum and vibration of those around you. That will change your vibration and move your momentum into the same direction as that of the complainers. If you had good momentum going and the day was moving along fine, you most likely will find that things are not so great now and you don't feel as excited and happy as you did before your "break". In fact, you might wonder what happened to your good mood or you are confused as to why you're tired all of a sudden. "What's going on?" you're thinking. "I was in such a great mood before and now I'm grumpy". Or, you might not be that aware. But, once you've begun to pay attention to your vibrations and your momentum, you will notice that things are different. Then you need to track back to where you've been and what you've done. Once you start tracking these things, you will know how to change your behavior.
It's imperative that you hang out with people who will help your momentum continue in the direction you want it to go. Whenever you start hearing stories from yourself or others, ask yourself "is this the direction you want your momentum to go in". If it's yes, then continue with it. If not, then go do something else.
Stay away from the water cooler is my advice. Let others talk but don't participate. Your momentum depends on it!