The psychological impact of making a large purchase all at once versus employing a DCA strategy can indeed influence one's perception and decision making process. When purchasing everything at once there a sense of commitment and finality which may lead to feelings of regret or doubt if market conditions change suddenly.

On the other hand DCA spread out the investment over time reducing the immediate impact of market fluctuations and potentially alleviating regret if prices drop shortly after the initial purchase. This approach can provide a sense of security and discipline as it minimizes the risk of making a significant investment at an inopportune moment.

Both strategies can lead to profits over time provided that the investor has the patience and commitment to hold onto their investments through market fluctuations. The key lies in maintaining a long term perspective and staying focused on one investment goals rather than becoming overly influenced by short term market movements or past decisions.