What motivates you in your senior year of college?

Junior here but felt similarly after receiving an SA offer for next summer. Here are some ideas that I learned from Kurt Vonnegut, a man who had spectacular insight into the human condition:

Pay it forward: 

I helped found a new finance club on campus and am involved with multiple groups as a mentor. Giving back is a big part of my school's culture, so I've been paying it forward double. Also, I'm regularly surprised by how wise my underclassmen peers are and what they can teach about business and life. I've struggled with nihilism and suicidal ideation, but helping my peers achieve their professional goals has been a big help. Here's a relevant Vonnegut quip:

We are here to help each other get through this thing, whatever it is.

Engage with new ideas: 

I have personal interests in philosophy, psychology, and leadership, so I've been spending a lot of time reading studies/biographies/literature and finding someone to share these ideas with. Seek out people who are intelligent, well-traveled, open-minded and willing to get drinks with you. This will look different for every individual, so explore your interests. Here's Vonnegut's advice to high school students:

What I had to say to you, moreover, would not take long, to wit: 

Practice any art, music, singing, dancing, acting, drawing, painting, sculpting, poetry, fiction, essays, reportage, no matter how well or badly, not to get money and fame, but to experience becoming, to find out what's inside you, to make your soul grow.

Forget about goals:

Finance students (myself included) are often stuck on the hedonic treadmill seeking the next most prestigious goal. A good friend (and prestige addict) of mine spent his entire undergraduate with GS IBD in his sights, and now that he has it, he's set on MF PE. I find Vonnegut's conversation with fellow author Joseph Heller helpful: 

Joseph Heller... and I were at a party given by a billionaire... 
[Vonnegut] said, "Joe, how does it make you feel to know that our host only yesterday may have made more money than your novel 'Catch-22'...?"
And Joe said, "I've got something he can never have."
And I said, "What on earth could that be, Joe?"
And Joe said, "The knowledge that I've got enough."

I hope you find what you are looking for OP. Enjoy your senior year!