It is important to build a good social network. You never know who's help you may need.
As I mentioned in Odd Jobs Can Pay Big, I install window blinds for the my neighbors to make some extra cash on the weekends. Today, I outfitted my neighbors home with new blinds. I made some extra money, but I also established a working relationship with them.
If I need someone to feed the cat when we are out of town, that person is now an option. If my neighbor needs some help moving heavy furniture, they can now ask for my help aswell.
After finishing the blinds, I cleaned up, and started walking back to my house. I noticed my other neighbor just happened to be on his way to the local dump, perfect timing. I gave him some cash, and he let me throw my oversized blind boxes in his truck. I can't guarantee that things will work out this perfect regularly, but the more people you know, the more opportunities will present themselves.
Basically, go the extra mile to become friends with the people around you. You never know when you might need them. It doesn't take very much effort, and the return can be great. It is nice to be able to call your computer savvy friend, when your internet goes down; or if you're able to consult a contractor friend when starting a home improvement project. It is human nature to seek advice from you peers, and the broader you social network is, the better advice you will receive. Friends can make a world of a difference when solving a problem.