Perhaps the best thing about My First Conference was the chance to hang out with friends and/or colleagues. The other three grad students from my lab were there, and for the most part we were attending the same sessions. We formed a peanut gallery during the talks, exchanging whispered comments and questions about the talks in progress, and often remained together for meals. It's entirely possible that if they hadn't been around, I'd have spent Friday afternoon attending talks not very related to my research and burnt myself out, instead of heading out to a two-hour "happy hour" before our lab reunion dinner.
I also got to see some old friends who have moved on. My main collaborator (aside from my advisor) graduated from post-doc in our lab to professor in a different country a few years ago. After two years of mainly communicating via email, it was incredibly refreshing to sit down for an hour and brainstorm ideas in real time, with sketches that don't have to be scanned or created in PowerPoint. Our former lab coordinator, now a grad student in another state, was also there, stopping by our posters to catch up on all the news and progress, joining us for dinner one evening. In a career that feels so isolated - just me, my computer, and sometimes my Internet connection - seeing people in person and having whole conversations was a welcome experience.
The downside to all this socializing is that I didn't take full advantage of this being a local conference. I could have brought a bagged lunch most days, and had late dinners at home. Instead, I wound up with a coffee every day, lunches out, dinners out. I spent my entire "fun" allowance for the month in just four days, and four days at the beginning of the month at that. It was completely worth it, but I might have a hard time remembering that at the end of the month when I've had three months of bare-bones activities.