For now, I'm going to focus on just one aspect: what can happen physically and emotionally and spiritually, when people get 'stuck' in the wrong season. (This is a big topic, so G-d willing, I'll come back to it again in the future.)
Let's start by spelling out the five seasons, and what each usually represents:
Winter: New beginnings, internal growth, depth, introspection and profound self-awareness
Spring: External growth, energy, determination, movement, change, action, 'doing'
Summer: Excitement, maturity, bounty, fullness, 'peak performance', joy
Indian Summer: A time of transition and change; stability, staying in the comfort zone
Autumn: The 'old' is dying to make way for the new; bare, harsh, cold, uncertain, lonely; but can also be very beautiful
Each person will go through these seasons in their own life a number of times, but the problems come when people get stuck in a season that they should have outgrown, already.
Typical examples are when people try to hold on to jobs, or relationships, or attitudes and beliefs that stopped being useful for them a long time ago. If G-d is trying to move a person out of their comfort zone, for example (which is typified by 'Indian Summer'), He'll usually send louder and louder wake-up calls that something needs to change.
People can, and often do, ignore these wake up calls for weeks, months and even years. It's very hard to pick uncertainty over stability, and to let go of things we're used to, even if they're no longer serving us, and are actually starting to hurt us.
If a person's in a job that they hate, for example, it can be very hard to make the decision to leave. It takes a lot of emuna to leave the comfort zone and jump into the unknown.
But if they don't jump? Then what?
Usually, they'll feel more and more miserable, sad and stressed at work. If they continue to hang on, then the problems will move out of the emotional realm, and into the physical.
The Indian Summer meridians are spleen and stomach. Stomach meridian speaks for itself: unhappy people who feel stuck in their lives often don't feel like eating, or start eating way too much. They get stomach ulcers and acid indigestion; they find things difficult to swallow.
Stomach meridian time is 7-9am - the time you need to wake up and head off to work. People holding on to a bad job probably won't feel too good when they wake up, and they may well feel nauseous or have an upset tummy.
Now, what about spleen? Spleen meridian relates directly to our happiness, our ability to assimilate things like food and emotions, and our immune functions and energy levels.
When spleen gets overwhelmed with toxins (as I've written about elsewhere) - our happiness and energy nose-dive, and we get more and more prone to feeling ill, exhausted, down and depressed.
These are all typical symptoms of people who are somehow 'stuck' in a comfort zone that is no longer useful for them.
The good news is, that things can change very quickly. I knew someone who was starting to experience all sorts of aches, pains and minor illnesses as a result of staying in a bad job. After a few years', they decided to quit, even though they had nothing lined up, and their health, vitality and happiness radically picked up within a couple of days.
G-d is sending messages to us, especially via our health, all the time. A person in Autumn time who isn't working on their emuna may well experience issues with their breathing and stress levels (lung meridian) or with lower back pain, as too many toxins start to back up in the body, instead of being easily 'let go' of. (large intestine).
People stuck in Spring, where 'determination' can easily degenerate into anger and aggressiveness, may shout a lot and feel like they're stagnating if they can't get people to move as fast as they want. This can show up, physically, in all sorts of 'detox' issues involving liver meridian, especially if the anger is repressed or turned inwards, and also issues with gallbladder meridian. And so on, and so forth.
The key is to remember that there is a time for everything, and that G-d is running the world. The more we work on our emuna, give things back to G-d and go with the flow, the better we'll start to feel, in every sense of the word.