What She Thinks Of Your Friends

It's important that your girlfriend likes your friends- but it's also important she doesn't like your friends too much, if you get what I mean. What you want to achieve:

She likes your friends in a friendly way. The signs:

• she regularly hangs around them
• she seems to genuinely enjoy herself in their company
• she talks abut things they have done with you when you're alone
• she doesn't mind having to hang around them
• when she's in their presence and you're not there, it's not all awkward and silence
  
• her friends are friends with your friends

However, these two can be bad, particularly the second:

She hates your friends.

• she loudly expresses her dislike: sighs when you make her hang out with them, complaints, etc
• she wouldn't hang out with your friends unless you convinced her to
• she is normally talkative around you, but is really cold to your friends
• when you're not there, she doesn't attempt to make conversation with your friends
• she hates it when you can't be with her because you're doing something with your mates

She likes your friends... a little too much.

• Yep, she definitely hangs around them all the time
• she laughs harder at their jokes than yours (and not just because you're unfunny)
• she flirts with them (see this post, but apply it to your friends)
• she's spending time with them when you're not around
• she's starting to spend more time when them than you

Your girlfriend's relationship with your friends is vital. Monitor and observe it well.