Better Communication Skills
The more people in your life you have to communicate with on a regular basis, the better you'll be at expressing yourself properly. People often attribute social awkwardness to introverts, but this isn't the case. Anyone can be socially awkward, even if you're aren't shy. Perhaps the worst perpetrators of social awkwardness are those that don't realize they have a problem communicating.
If you have frequent arguments and misunderstandings with people, you should look at how you interact with them. Having more friends in your life will force you to be more aware of the things you say and do.
Help With Babysitting and ChildcareThe more people you know, the bigger support network you'll have when you need it. One area people often need help with is childcare, which includes finding quality caregivers and childcare services. This is where having friends that have a lot in common with you can help. You and your friends can trade off helping each other with babysitting, or can probably recommend someone.
Better Networking and Job Search
Some people seem to rebound very easily from a job loss, with others seem to always have the "in" on new jobs that open up. That's because people tend to hire and recommend people that they know personally in some way, either as an acquaintance or friend.
Having a variety of people in your network can help you find out about new opportunities you might have missed.
Getting Over a LossAny type of loss (divorce, loss of a loved one, or the like) can bring heartache, and if you wallow alone it will take you that much longer to recover. Friends are great at not only allowing us to vent, but also telling us to get up off that couch and get out. They help us do the things we wouldn't normally do on our own, which can help you get over the loss of a relationship or job that much easier.
Support Life Changes
When you decide you want to switch gears and change your career or have a child, friends can make the transition that much easier. Even the most positive of life changes can put you under stress. You might even begin to feel deep down that you "can't do it." But friends will assure you that you can, you will, and you'll be awesome.
It's not just lip service. Good friends see the potential in us when even we can't seem to spot it ourselves. They'll not only help you celebrate your new life event but give you a gentle push when you begin to doubt yourself.