Keeping secrets is hard. As early as high school, I remember feeling a sense of tension within myself between aspiring to be a frank and open person while trying to remaining somewhat unexplainable to those that didn't know me particularly well. Those approaches seem almost mutually exclusive to me today, which explains the confusion I felt about this during that time.
The passing of time breaks down pretensions and gradually reveals the underlying and most fundamental aspects of your personality. The deliberate plotting and planning of the early stages of identity formation often fade away once the school gates are slammed shut for the last time. Trying to be enigmatic may have seemed useful to me but it was in conflict with the core of who I was and it certainly isn't something I've grow into particularly recently.
So why do we choose to keep some things from other people? We withhold information to protect ourselves. Keeping secrets can, perhaps temporarily, protect the way we are perceived by others. We can also withhold information to protect those close to us if we feel that sharing would be burdensome or cause pain to the people who care most about.
I have always found myself compelled to tell people things. Personal things, embarrassing things, things better left unsaid. I share the way a student drops a heavy backpack when they arrive home from school. My routine is part a healthy process of reflection, part unhealthy self-depreciation. Why else would I share that it took me thirty car trips from the old place to my current flat before I could find my way without the GPS? That's the sort of thing that could have easily stay buried, but know you know.
There can be no doubt this is partly a selfish practice. I unpack thoughts to lift my burdens, to quiet the rattling in my head. When something is outside of me it is easier to examine with critical distance. These tendencies are likely a net positive for my psychological health, but it's certainly not without its drawbacks.
Lately, I've been trying again to hold onto things a bit more. It is important for me to be able to bring this aspect of my life into balance. Discretion can be a skill just as it can be a crutch. I'd certainly advocate living an open life, but like anything else we need to know when to use the different tools that are available to us and to make sure that we're sufficiently skilled in using them when we do.