At first I read the title as "Axes can be good things
"... hmmm, is this a mass-murder node?
Anyway, I digress. For me, my ex's are a standard with which to judge future potential girlfriends. I have only briefly talked with my latest ex and she is nothing but bitter at the world. Now that she is my ex-girlfriend I am able to see her in a different light, and realize that she wasn't meant for me. And I am able to see clearly all the things that weren't so good about her; things like her immaturity, her inability to manage even small amounts of money, her stubbornness and her lack of ability to communicate, the later of which was a stumbling block for us.
So when I met my latest potential girlfriend and we started dating, I was able to more clearly define what I am looking for. Can she talk about things? Has she reached a certain level of maturity? etc... it's not that I can't let go of my ex-girlfriend. I've already done that. So I guess I'm not comparing future girlfriends to my old ones, but instead using old girlfriends to help me define what I'm looking for and to help me decide what's important to me in a relationship.
As for having ex's in my life, I have yet to have a girlfriend that I continue to have a actual friendship with after a breakup. It's not so much that our breakups have been on bad terms so much as for me I find it hard to just look at the fruit after you've had a taste of it.
I'm not sure why, but someone said that my write-up made it sound like I am only only interested in girlfriends for sex... maybe it was the "fruit" comment... so I'll clarify (not that you care). That isn't the case. I like having a girlfriend so that I have someone to share my life and experiences with. And so that I have someone to talk to; about anything. Sex is just a good side effect of the situation. I have lots of friends who are female, and tonnes of friends who are male (most due to my Army reserve service) and I enjoy doing things with them too. And the fruit comment? For me, that's just how I feel. So there. :)