Most Helpful Girl
A wide back is a huge turn on. The V shape is a gorgeous asset in men
Most Helpful Guy
A thing that often is considered attractive? Broad shoulders /wide back, no doubt.
Often "cave man thinking" is a useful tool, that also applies here.
Guy with strong legs: Can push/pull a lot of weight (such as hoes).
Guy with strong arms Can hit hard (such as a Smith might) or move the arms against resistance (ever seen an animal tamer?).
Now, what will the caveman think when seeing a 6'3" Russian dude that takes up the entire doorframe? "Better not fuck with him".
In other words, guys with a large torso are often good at protecting, which is desirable.