Project implementation have its ups and downs. For many, you will get your usual freeloaders and NATO (No Action Talk Only) members. In worst case, you may even get a self proclaimed project manager who is actually a project admin. The key is to ask yourself what you aim to achieve. This is also why you must stay positive in your project.

Why Stay Positive
If you are familiar with project implementation, you will realise that each ending provides better beginning. We tend to focus on negativity and grumble on how the project should be run. As you gained exposure, you will look back and realise staying positive is a better option. Being positive improves your oversight and gives you clear direction in the project.
Moving On
It is wise to stay positive and move on to the next project. There are some who cannot shake off negative energy from previous project. Some may even have PTSD (Post Traumatic Stress Disorder) from project. The right approach is learning to be positive and moving on with the correct learning. Of course, you may encounter good mentor who advocate positives. Steer clear of negative people and team members as they do not help in your project learning.
Project implementation can be fun and mentally challenging. I find it enriching to be positive in every project. Of course, I have also been to the dark side. You should also start to move on with positivity and leave your baggage behind.