What do you do if your actions unintentionally create a negative and exclusive culture?

You have to acknowledge the energy you bring into the room look at how your actions, words and demeanor/body language all influence this. Are you approachable? If someone asks a question, are you observant of the tone you're using to answer them? Is that tone warm and inviting, relaying that you value their input? Or is it short because you feel stressed with your deadlines or workload... giving the other individual the feeling that maybe they shouldn't have even asked? If the latter, you must recognize that you are contributing to the negative culture, which in turn only makes your job harder. You can change this though. Ask for feedback from your team, validate their experiences with you, and be mindful and present in your conversations.

Wen you do this, always keep in mind "it's not about the people, but about the processes, or the dynamics between them (and also the systems around)". Hence you want to approach it with a mindset that will help people taking the information, free from the personal. I have seen managers, with the best intentions, still creating toxic work environment. At times, we can be trapped within the automatic behaviours our brain is inviting us to choose from, in reaction to our systems' dynamics. We need then to move from reacting to responding. This often creates discomfort. Why? Because we agree then to step into uncertainty, and our brain does not like that, at all. Welcome to the world of #selfleadership :-)

In order to analyze the situation to determine appropriate action plans, you need open and honest feedback. Make yourself available and encourage dialogue. Ask open-ended questions about challenges and request constructive criticism. You want to know how to make it better and easier for your team. You want to remove the hurdles that get in their way as much as possible. Gather insight, the good and the bad, as this will help pinpoint the problem areas in order to address them properly.

Once you have the data, you are able to construct a plan... Have your team involved in this development process. That demonstrates to them that you value their input. It's cliche, but there is no "I" in Team, and you want your team involved in the creation of an action plan. Break it down step by step. When there is more collaboration in this manner it leads to inclusion, transparency, and better communication. Then hold yourself accountable to reflect (personally and as a group) on the changes as you progress through the plan.

Whenever possible I love adopting a "proactive mindset". The question then becomes "What do you do to ensure you, and people around you, like your team members, your peer, demonstrate behaviors which support a constructive environment." And yes I use constructive, to avoid the bias of "ongoing eternal positivity". Negative emotions. Negative sensations. Both have a place within a team, or a person, evolution. What we are aiming for at all times, is for these experiences to bring constructive learnings. To my question above, a good answer is : taking a moment to create a "team charter" or "a team manifesto", to have every body really clear about expectations within the work place.