I'm guessing you are the people you are describing.

How I meet new friends is being friendly and starting conversations with others.

How to become more than acquaintances, I ask to exchange numbers and hangout. Then I choose to get to know the person more.

If you have trouble leaving the house, I would take one step at a time going out and about when getting to know others to overcome your sensitivity.

For a busy person you only can do so much hangout or talk on the phone when you do have time. you can always e-mail back and forth between the hours that you have to spare.

And last but not least is that you need to get to know someone more to know if they are someone who you want to be friends with. You learn through time...

Plus if someone is complaining too much you can always tell them that you would like to talk about something more positive.