I don't mean to offend anyone; I know people that do these things; I have been tempted to do them myself, so let's continue. First off, people use sunglasses and umbrellas for genuine, authentic reasons. No one wants to get soaked or have to squint all the time. This does not explain, however, wearing sunglasses inside or carrying an umbrella big enough for three people to comfortably fit under.
First, let's hit sunglasses. This seems pretty clear to me (haha, not tinted). I am very expressive with my facial expressions and eyes and many people give away their intentions with their eyes. Like poker players, I believe many people wear sunglasses to make themselves harder to read, so they can better control their interactions with other people. Maybe it's a self-esteem issue or a control issue, but either way I think it is not beneficial. Either learn to control your emotions or deal with other people being more aware of your intentions. Be real.
And then, umbrellas. Nobody likes to carry one of those crappy umbrellas that isn't even rounded. But why use one that is so huge? I am not an umbrella guy, I'll say that straight off; carrying an umbrella all day would almost be as tedious and emasculating as carrying a purse to me. I am tempted to accuse guys who carry long umbrellas of compensating for something, but I think that is unfair. Maybe it's just an American culture thing, we like bigger, it must be better. I say be modest, though, unless you have someone to share your umbrella with. Two-tiered or three-tiered umbrellas are overkill.
So for those walking around campus, beware, you are objects of my study of human behavior.
RossDaddy