I recently went on a team outing where we took an improv class. One of the ideas of the class was that you need to accept the idea provided by your partner(s) in the scene. If you contradict that idea then you are taking away from what they are trying to build for the audience. The core idea is to "say yes" and go with the flow of the scene. This will tend to lead to funnier moments than if you are are fighting against your partner(s).
This made me think about how life outside of improv and comedy is normally not this way. The instructions to the class to "say yes" are needed because this is not the way most people behave most of the time. How often do you hear someone disagree with a suggestion someone else gave them? It's almost like a reflex to some people. No matter what the suggestion is or who it came from they disagree with it immediately and clearly couldn't have considered the suggestion. I wonder if that sort of mindset leads to a negative outlook on life? By always being negative you only see the world through a negative lens.
I think it would be better to try to be the opposite. Say yes. If you are given a suggestion, start out by accepting it as a good idea and that you should follow the suggestion. If you start in a positive place and you come to the conclusion that you should not follow the suggestion, then at least you reasoned out why it wouldn't work as opposed to dismissing it out of hand. You will have a solid reason for not following the suggestion and you will have thought through your options. You will likely be grateful for the suggestion and feel like it helped you understand your situation better, rather than thinking of it as a waste of time or a hopeless idea that would never work.
I also think it is a good idea to say yes when someone asks you for a favor. It is generally going to be easier to just say yes and do a quick favor for someone than saying no. Most people are not going to bother you with some overly complex and difficult task, they are going to ask for something simple and something they themselves would be willing to do for you in reverse. If your first reaction to, "Hey could you grab me that item over there?" is yes of course, then both of you are going to end up happy. The person asking gets their item and you never let negative thoughts enter your mind so you are happy to have helped. If instead, your first reaction is "I don't want to do that," chances are you are going to end up doing it anyways so that you don't look like a jerk. The other person is going to either be happy if you hide your annoyance well or feel bad that you are annoyed and probably not want to be around you as much. You are going to be annoyed and unhappy over something small and insignificant.
I know that for myself I do not enjoy being around people that are always negative. I do not like talking with people that immediately shoot down my ideas without thinking them through. I want to be happy and positive and if someone does not help me achieve that, I would rather spend time with someone else than them. I believe that keeping yourself in a positive mindset will lead to a happier life. If you do not fight against things and go with the flow, people will be more interested in being around you. You will likely have better and more experiences as well because people will invite you to do things with them rather than avoid you whenever possible.
Say Yes. Stay Positive. Be Happy!