I've been observing others and examining my own past to see why we lack inner peace. A lot of things out there in the world go wrong and they do bother some of us, the more conscientious ones; but overall, things that happen close to us generally affect us more.
Here are some examples showing how we can lose peace. Someone is given a much better Christmas present than what you've received. Someone who joined the company later than you gets promoted first. someone puts some kind of extra burden on you either knowingly or not. You suffer a financial loss in some way. Someone who owes you a debt delays repaying you. Your rich friend buys a lot of things you cannot afford. Someone's behavior or speech annoys you. You are misunderstood by others. Someone cuts you off on a freeway. Such examples are many and common. The emotions involved are anger, envy, jealousy, self-pity, fear, frustration, distress, etc. The causes are a big ego, selfishness, being judgmental, impatience, lack of humility, lack of trust in God, etc. As a result, you get weighed down with a heavey heart.
Here's how all can change. Let Christ take over your life and all the above-mentioned causes can be removed. There is no other way to free yourself! God does not weigh us down; instead, he lifts us up as high as we wish to go. He is God and he is love. So, there are many, many things in life that constantly weigh us down; but only one God who can lift us out of the pits and make us live in him in peace and freedom. (This is absolutely true as the saints and many others have experienced it.)