Well that could be a productive exercise for you too then!! Keep in mind most of the subjects you are thinking of approaching think they are as socially awkward as you might think you are. Generally a warm smile and something you find intriguing about them is a good ice breaker. I'm the weirdo with no holds bared tho, I ask strange personal questions about why they live in the streets or why they chose too, what they like, dislike about it...many people want to tell their story to anyone that might care because they feel invisible. The homeless is some of the easiest to talk to. I don't know if you smoke or not but offering them a smoke or 2 goes a long way. Sad guy too probably would be an easy one for you.

Here is a social experiment for you and see for yourself. Take a candid picture before you approach someone like you did and then take a moment to hangout with them and then ask to take their picture for a project of yours. See the difference.

I'm naturally an introvert and I like to "people watch" and analyse different things and scenarios but my life circumstances don't really allow me the chance to be shy since my work surroundings are always changing given I repair infrastructure at various oil/ energy facilities etc across the province and originally come from a political family in a small region.