To be careless in making decisions is to naively believe that a single decision impacts nothing more than that single decision, for a single decision can spawn a thousand others that were entirely unnecessary or it can bring peace to a thousand places we never knew existed.
We may talk lightly but never carelessly. We keep at bay the flow of common, ignorant thought which runs its damaging course through the pathways of ordinary human conversation.
You become a house where the wind blows straight through, because no one bothers the crack in the window or lock on the door, and you’re the house where people come and go as they please, because you’re simply too unimpressed to care. You let people in who you really shouldn’t let in, and you let them walk around for a while, use your bed and use your books, and await the day when they simply get bored and leave. You’re still not bothered, though you knew they shouldn’t have been let in in the first place, but still you just sit there, apathetic like a beggar in the desert.
For those constantly full of joy, they sometimes feel a little guilty for always feeling so good. That guilt is compassion: it flies in with an attempt to share one's joy with others who do not have it.