In Instruments in the Redeemer’s Hands Paul David Tripp gives several reasons (and I added one) why we prefer the superficial and casual over against truly getting to know one another.

1. Busyness. This traps us into having superficial, casual conversations. Most people, even if they wanted to get to know other individuals, simply don’t have any margin in their week to do so.
2. We’re unique. We buy into the lie that we are unique and struggle in ways that one else does. Many wrongly think, “I don’t need to open up my life because no one can truly identify with what I’m going through.”
3. We prefer darkness rather than light – we find the searching light of true friendship a little intimidating. True friendships call you out of the darkness of personal privacy into the loving candor of mutual concern. It moves you from being a sealed envelope to being an open letter.
4. We simply don’t care. This was shared by a leader in our church and there was a noticeable sigh as he said it; the sigh came because most understood this was all too true.
5. No one asks. Put simply, most of us do not take the time to get to know others.
6. We prefer the comfortable. Getting to know someone brings in all sorts of issues, messes, chaos (joys/blessings too, though we don’t focus on those) and we’d rather live comfortable lives.