Fear - Most people fear rejection. All of us have a vested interest in being accepted and liked. What's the worst that can happen if someone doesn't connect with you? You're still the same unique you.
People underestimate their value - So many of us don't see ourselves and our impact on others. It's very empowering to know your own worth (and you need it in today's competitive job market). So..
Make a list of all your positive qualities - then ask yourself, "why wouldn't someone want to meet me? I have a lot to offer".
Surround yourself with supportive people - there's nothing like having someone in your corner to cheer you on. If you can't see your great qualities, most likely others will.