Chat with a homeless person. No social worker talk. Don't ask them anything about how they got there, how their life is, what they need, etc. etc. Just treat them like a normal person: weather, sports, local traffic, etc.
Those people probably aren't good candidates for a friendly chat anyway. Believe it or not, there are plenty who don't want anything from you.
Normal people interact with us all the time.
You might try just being friendly with people some time. It's only weird if you go about it in a weird way.