I had a friend. Well, yes, I had. I stopped taking his calls because he was only interested in getting free work out of me.
The only times he used to remember me were the times he needed help. Maybe something technical or plain advice. Considering him as a friend I used to keep up with his tantrums, that was until he started bugging me too often.
You see, friendship or any relation isn't a one-way street. You can't just keep on asking without giving something in return as well.
Sure, we make friends, meet new people or in more technical terms "network" to get our work done. However, networking solely for selfish reasons is bad, like really really bad.
If you really wanna network, really want to ask for favours, learn to care for that person first. That is what turns strangers into friends.
Don't ask only for favours, understand their feelings and respect their privacy.
When the time's right, you'll earn your right to that favour. Till then, keep investing.