I've been a teacher for almost 10 years and have worked almost every summer to earn extra money. There are 2 exceptions: when I got my first teaching job, lived at home, and made more than enough to take care of my bills, and the summer after my son was born (but I still worked 2 weeks of summer school so I don't know if it counts).
This year I'm teaching 3 weeks summer school again. I'm lucky that my mom is able to come down and watch E or this wouldn't happen. However, it's sometimes hard not to feel upset when I realize that I barely see E during the school year work week and, though the hours are better, I'll be gone again during the summer. The mommy guilt will kill you if you let it. Also, the summer is when I mentally recharge from everything so I'm fresh and ready for another year with my students.
The money is going to pay the bills, as well as pay for next year's vacation to Disney (yay!); therefore I can't complain too much. I need to work and there's a venue for me to help kids, which is why I became a teacher in the first place. Let me end this by saying that maybe money doesn't buy happiness, but it certainly helps.