The advice I'd always been given is that novice investors should never try to play the market, no attempts to buy low/sell high or pick additional stocks, and that seemed very sound, as I have no experience in the field, so I just kept my hands off and assumed that the fund manager was doing whatever needed to be done.
The investment decisions people make are often influenced by cognitive biases that can lead to irrational decisions or behavior contrary to personal financial goals. Cognitive biases, like the status quo bias, showcase a tendency to prefer existing circumstances over change.