There's a mood shift you experience as you enter the second half of your college experience. Freshman year was fun--there's no other word for it. All my classes were incredibly easy and I spent a majority of my time hanging out in the cafeteria or McKinney's. I went to Dwarf House and goofed around and it was fun.
My sophomore year I started to get a little more serious about classes, but I still did a good bit of goofing off. Most of my free time was spent with friends and again, it was lots of fun.
This year is different. I'm more driven, less inwardly focused and more concerned with the future. Many of my friends are graduating and they're leading by example: what will I be doing in two years? Where will I be? What kind of plans do I have for myself? I'm still having fun, but the purpose is not the fun. The purpose is for what's coming next.
But it's still a lot of fun.