When I'm at work I only want my shift to be over with so I can go home. I spend my time at work thinking about things other than fixing trucks. I think about building stuff out of wood, spending time in my favorite flight sims, mowing the lawn etc. I don't want to fix anything because that's all I do at work. Fix things. You know what? That doesn't always happen. I think there's two kinds of people that work as mechanics, those who enjoy the challenge of fixing things and those who are there because it's a job. As much as I'd like to deny it, I fit into the first category. As mechanics we feel the need to fix things when they're broken. We can't avoid it even if we try.
For example, I'll tell you a little story. Last December I was traveling to my sister's house for Christmas and pulled into a truck stop to take a break. I topped off my fuel tank and went inside to take a leak and get a soda. On my way back out I noticed a trucker parked off to the side with his hood up. I wondered what was wrong, but continued walking to my car. As I was starting to leave I thought about his situation and felt a bit guilty. He was probably wanting only to finish his run so he could get back home to his family and now his truck's broken. I turned around, pulled up next to him and asked him what was wrong. From what he said I quickly determined that his fuel had gelled (it was very cold that day). He mentioned that he had new fuel filters and knew how to change them, but didn't really know how to deal with gelled fuel. He accepted my offer to help and went into the truck stop to get the fuel liquifier I told him to buy. In short, I got his truck running. He was grateful for the help and offered me some cash. I politely refused. I told him some BS about it being Christmas and he could repay me by doing a good deed for someone else who needed help. Part of my helping him was due to something my father had said to me, "If you can help someone, help them." The real reason I helped this guy is that I love the feeling I get when I fix something.
The other side of this is when it's my turn to be on call to handle the weekend and after hours emergency road service. I hate it. I enjoy helping people, but only at my convenience. Not in the middle of the night. Even though I gripe when someone calls for a service call, I'm fine once I'm on the job.