There are no single right answer because it really depends on the circumstances. Looking at the center mass which is the chest affords you to have your adversary's arms, hands, and hip in your sight picture - you have as much of his body covered. But looking at his eyes can help you too because many people have the bad habit of starring at where they want to attack, thus telegraphing their intent. This is especially true when they want to grab your legs to do a takedown because they have to see where your legs are unlike a punch to the head which you can gauge the distance to target simply from knowing where the chest is.
However, depending too much on your sense of sight is not always a good thing because in very close quarters such as grappling you cannot see things - you have be able to feel out his intent from the way pressure is exerted at the point of contact.
Focusing on one part opens you up to any other part he has to attack. Most schools teach to focus on the chest or shoulders which will just leave you open to kicks or sweeps. Focus on the entire person and more. If you are on the street and he is not alone you have to be aware of his friends around you. Don't focus on one area or you get hit from all other areas.
For you, your fighting "appearance" and manor isms should be no different than how you are not fighting. Changing your look or mannerisms telegraphs your intent and stiffens your body which you don't want.
Chest, from there u can use peripteral vision to see incoming punches without moving your eyes, and kicks.
Think about it, if they r sending out punch after punch, then is it likely they r looking at different places each punch will go?
You need to see the whole picture instead of focusing on an area or reging of the body.
I watch the eyes.
Most people tend to look in the area they are about to throw a punch into
LOL it doesn't matter to me. I look at many sports. Sports I wanna hit
most of the time I hear to the chest because its the center and u see everything coming and cant get deceived like eyes and really once I got deceived by looking to someone eyes, but why most UFC fighters look to their opponents eyes?
