When I started shutting down negative thoughts every time they popped into my mind or came out of my mouth I noticed a difference in my overall mood and mental health. Now, whenever I am around someone who is constantly spouting negativity I politely shut them down, change the subject or offer an alternative point of view to try and help decrease their negativity.
Yes, I try to see my world with rose-colored glasses, and yes I know everything is not perfect but keeping a negative attitude about it will change the outcome, but can change the journey. This isn't to say that I don't have my days where I slip up, but we all do, it's just a part of being human. I understand life is going to be hard but I want to make the most out of it while I can.
Studies have shown that being negative can increase your likelihood for mental disorders such as depression, anxiety, and even mood disorders. If you already suffer from any of these disorders then you know how hard it is to be positive even if it just for a minute, so just "deleting" the negativity will not cut it. Staying active in recognizing how it affects you is important, as well as completing tasks that you can help cut down on the negative thoughts, words or actions.
Taking time to be mindful in the morning before you start your day can create a positive atmosphere and may help replace the negative thoughts that want to come out. Writing down things that make you happy and then later going back and rereading them is another practice that helps keep me in a good mood when something has me down. Tracking the source of negativity is important, maybe it's a coworker, sibling or friend who make you horrible when you're around them. If it is possible delete those people from your life and if that isn't possible distance yourself as is feasible and find distractions from these negative outlets in your life.
When this toxicity of negative thoughts and words are gone, you can start feeling better and maybe along this process you will learn something about yourself.