The price of a bitcoin is influenced by supply and demand. When demand for bitcoins increases, the price increases, and when demand falls, the price falls.
It should be a common reason that it's about supply and demand. But the question is, what influences the movement of supply and demand? We can consider all things that make the market react to why people buy and sell, like, news, sudden events, big individual involvement, and many more.
When we are looking for a specific reason why bitcoin price surge or dips, we can look at some shared factors on the articles and news and consider those as references. It's a good read instead of just creating random thoughts.