I'm going to leave out some details here, but I'll give you some my reasons for why I went into academia.
1. I like to be more or less my own boss. Sure I have a department chair to answer to and the university in general, but I'm largely my own boss. I get to decide what science/engineering topics are cool and what research questions to explore. As long as I find funding for them, I can study what I want.
2. I get to choose what service activities to be involved with and I try to pick things I feel are important to my research, quality of life, or my community. I've joined committies because I feel the cause is really important and I feel like I have made a difference (particulary for women), and well I like to have a say.
3. I have a pretty flexible schedule. There is a lot of work to be done and with daycare hours I'm more limited to time the kids are in daycare or asleep. But, I can with the except of classtime move things around on my whim, as long as I keep up with the never ending list of things to do.
4. I can think about research problems that can improve the lives of people. I can stop to think about why and what the mechanism is. I don't alway have to be thinking about a product that needs to role out or the bottom line.
5. I get to hang out with really smart people (even if they are somewhat socially inept) and it's expected that I will always be learning something new. More over the sharing of knowledge openly is encouraged.
6. I get to mentor/teach students and watch them mature into engineers/scientists. I love hearing about where my former advisees and lab assistants have ended up. What they learned that is helping them now and what they wish they had known. This part of my job gives me great joy. I love giving advice about where to go for graduate school.
7. I also enjoy interacting with people from other schools/fields. It's interesting to learn how different things can be in the humanities. I love learning about new points of view (as I did when I lived abroad) and it makes me see my own field in a new light. (e.g. the humanistis jaws drop when I tell them our normal teaching load is 1/1.)
There are many frustrating days and I sometimes lose sight of these things, so I am trying to remember the good parts of my job. I also don't mean to imply that academia is the only place to find these things, although I think the student aspects are somewhat unique.