I believe many people are emotional and they oscillate between the fear of losing money and the fear of missing out. After a series of big down days, they fear losing money if they're exposed. After a series of up days they fear missing out if they aren't fully exposed. 

For example, a passive asset allocator is fully exposed all the time. So, passive asset allocators may be more likely to experience the fear of losing money after markets decline. That is, they fear losing more money after losses mount because their exposure to the possibility of loss is static, yet the magnitude of the possible loss is large. It seems a fixed allocation policy may have a difficult time with uncertainty because they depend on the direction of markets to create their results. I guess they may spend more time reading and watching the news trying to figure out what's going to happen next since what does happen next is what determines their outcome. However, they probably don't fear missing out as much. If you're fully exposed, you don't have to worry about missing out. So, it could be those who fear missing out (the up days) who are more attracted to a passive asset allocation strategy. While asset allocators risk losing a lot of their money, they don't miss any good (or bad) days. They get to experience it all. You may notice they say "we" in reference to the market. Instead of the market was up today, they say "we" were up today. Allocators like being "the market". That may work for them if they don't have that fear of losing money, or losing more money after they've already lost it.

Others prefer to rotate their exposure, but no one said it's easy. If they buy now, what if they're wrong? They risk entering just in time for the next leg down. If they don't enter, they may fear missing out. These emotions are especially present if their ego (sense of self worth) is closely tied to beating some index or benchmark. If their goals are instead their own, like "making as much money as I can without taking more risk than I can afford or handle" they may not feel the pain from the fear.

Like any kind of management, active risk management is a skill. Just as there are better managers of a football team, there are more or less skilled managers at most anything. Those who did exit early in the stage of falling prices and were able to avoid some of the recent declines now have to reenter. When prices are rising, those who don't really have a robust system start to fear missing out. Their system is their fear. Many people probably have more of a disposition between the fear of losing money or the fear of missing out. That is, I believe most people have the tendency to lean one way more than another. Those who mostly fear losing a lot of money may appreciate the potential of active risk management. Those who primarily fear missing out may be more likely a gunslinger who stays fully exposed. 

Yet, some people may oscillate between the fear of losing money and the fear of missing out on a daily basis depending on what the market did that day. For them, they are in a constant state of fear due to the lack of control they have on the outcome and their feelings. 

In my experience, wealthier people are more geared toward capital preservation than those who feel they need to take more risk to get ahead. Investor behavior is always what creates the outcome. In reality, avoiding large losses is the key. If you lose -30%, you need +43% to get it back. If you underestimate that fact and then panic after a large loss it will take a long time to get it back in a 1% savings account. Large losses are exponential; they compound against you. It's that power law that holds the key to good long term investment results. Beyond knowing the math, it's investor behavior that creates their results. To learn more, read Asymmetric and Exponential Nature of Losses

Trying to figure out what's going to happen next and oscillating between the fear of missing out and the fear of losing money seems like a tough way to go about it. 

I have to admit: I probably have other life experiences that better prepared me to embrace uncertainty and fear more than others. I may not fear the unknown like others seem to, or have a strong desire to predict it right. I enjoy watching the movie unfold rather that trying to predict how it will. My sense of self worth is never tied to the outcome. Since I don't have those expectations and my results aren't defined by them, I don't have anything to fear.