Email: trogan at umd dot edu
I really like the Firefox 3.5 interface because it's streamlined, attractive, clean, and easy to customize. It was easy to arrange it so that my bookmarks show up right next to the menu bar, and I have a few bookmark folders that by default open up into drop-down menus. I also like how big the back button is, since i use it all the time.
I dislike the UMD mail interface because it's hard to use, ugly, and inefficient. For instance, deleting messages requires clicking on a checkbox next to the message, clicking the Delete button, and then clicking Compact on the sidebar to get rid of all deleted messages. Alternatively, you can set it up so that deleting messages sends them to the Trash folder, but then you have to navigate to the trash folder and click Empty Trash to get rid of deleted messages.
I think the advent of text messaging has most affected human behavior in the past five years (assuming that you consider text messaging within the bounds of software technology). Five years ago, people who needed to ask each other short questions called each other, maybe exchanged small talk, which maybe led them to other topics, and eventually asked their question. Now, it's all business: just fire off a ten-word text message and you're done. No social interaction needed!
Look around you in your next big college lecture - I bet a large percentage of the students have their heads down, busily typing on their phones under those foldable desks. Phones with qwerty-style keyboards and tiny buttons have become much more popular. People text while driving, at the movies, getting their hair cut, standing in line, eating, walking, running, you name it. I read an article a few weeks ago about a girl who was texting while walking on the sidewalk in New York and fell down an open manhole. So clearly, text messaging has affected human behavior in a major way, for better or for worse.