Physical or verbal. No it doesn't happen often here, but it's still always on my mind.
Well, you said you're a big guy and tough looking, so that helps some. Learning some basic self defense things can help- you can learn some things from youtube videos that will help for basic self defense. As far as verbal, working on your verbal skills can help, there are videos on youtibe for this. Also youtube has videos for how to de-escalate a situation. These things could help. YOu can learn a few things that you can practice and they should help your confidence some.
I'm not big as in super muscular (or fat). I have a large frame that takes up space. I've wondered before why people in public who look like prey are able to walk around without fear while I am not.
Learning self defense from a video doesn't work. You need to spar. Verbally I'm good actually and that's thanks to reading, but verbal ability drops when anxious.
It is suprising the number of cases of people who have learned self defense from a video ro a book who have successfully implemented these lessons in real life. Sparring is not needed as much as people think unless you're going against a highly trained fighter, which most people are not.
I'll explain one interesting example I read in a self defense book. A lady was just starting out in a training class, this was right at the beginning of the class before she had any training. She was five feet tall, 100 lbs, and middle-aged. The class was in how to defend against knife attack, and the instructor was over six feet tall, muscular, and he had been teaching this class for over twenty years. The authors of this book strongly believed in the power of mind-setting for self defense, and they were in class in order to teach some people about this. They really thought that the instructor was somewhat arrogant about his skills. So the idea is tha the instructor is going to attack this lady with a rubber knife but that before he did these instructors would help her with her mindsetting. She had no previous self defense training. So they took her aside where no one else could hear and helped her with mindsetting. They told her to think of herself as an American Indian woman, since they are known for fierce fighting, and that this man was coming to kill her kids, and that she was the only one who could save them. They gave her no specific instructions for what to do, they just worked on her mindset and got her into a really frenzied state where she really believed that this man was coming to kill her kids. So then they got those two together in the gym. The lady came at this guy in such a frenzied state that he was totally unprepared for it. She charged in and knocked the rubber knife from his hand before he knew what hit him and it dropped to the ground. She picked up the rubber knife and stabbed him a half dozen times in the groin and then jumped up and knocked him to the ground and stabbed him in the neck and heart oevr and over very quickly. This guy had been training people for over twenty years how to do things in a certain way and nothing like this ever happened before, but he had never been faced with such a frenzied, out-of-control attack. So mindsetting is often a lot more important than training.
You can learn a lot about palm strikes, hammerfists, and other strikes to the neck and face and gron that you can do quickly and then run. You don't have to spar, most of the things you do for self defense can't be doine in sparring anyway, like attacks to the groin and eyes, and attacks that could break the neck, etc. You can learn a lot from videos and books that can help for self defense. If you can go to classes this will help in addition, but they are not needed to learn important things that you can use for self defense.