Many good trading opportunities come from chasing gains. When prices rise, we hesitate to chase and end up missing out as they continue to rise. Many significant losses are caused by holding onto positions too long, and when prices drop, we refuse to believe they can fall further, only to see them continue to drop.
Chasing gains and cutting losses is actually much harder than we imagine, largely due to human nature and the lack of mental preparation.
If you feel you have issues in this regard that have caused you to miss many opportunities, consider training your instinct to act by starting with amounts between 10U and 100U. When you find a promising asset, buy in immediately with 100U without looking at the price. The positive feedback from making the right decisions far outweighs the excitement of making the wrong ones. The same applies to held positions that are in a loss; the hardest part is taking that first step. Once you make that step, you will gradually accept the loss, allowing you to seize other better opportunities without being stuck due to previously held positions.