I believe we can summarize it in one word, but we need to fully understand why that word.
Keeping in mind the "world" necessarily implies much more than just the "earth".
Whether you are starting your studies in the “micro” of biology and chemistry, in the “macro” of astronomy, or the invisible binding laws of physics and mathematics or if you already have your PhD in these. Whether you are a big dreamer, an inventor, or an artist … you are always just barely scratching the surface of what is to discover, capture, invent and understand.
Since in the world some live in abundance and even excess and others in need, some live in stable environments others in unstable sometimes ruthless environments, some seek out their own gain regardless of cost, and others just make ends meet whilst trying to affect positively the lives of those they love and those around them. Since there exists a form of justice, and yet injustice, kindness and cruelty.
Whether positive, or negative, in beauty or disgust, whatever you focus on and spend time on, it can always be … overwhelming.