True Neutral- Tryptamine.
He'll be your closest lover, ultimate heartbreaker, best friend, worst enemy, and indifferent to it all because he does what he wants for himself no fucks given.

If you look at Good vs Evil as Selfless vs Selfish, this doesn't seem neutral anymore. 

 That's just because I'm a Gemini.

That depends on how much the Gemini does or doesn't value "stuff" from what I've seen. 

While it produces a surprising amount of thieves and music people for some reason, some of them give their shit away just as readily or otherwise find themselves wrapped into causes they didn't plan for. 

Selfishness is present in every sign potentially in one form or another. 

 Zodiacs dictate nothing about personality unless it's just somebody intentionally trying to live their zodiac.

Alright lets go through this step by step. 

Do you think seasons have any effects on people? 

 Yes.

What would you say those affects are like? 

What are your thoughts on data like this: https://en.wikipedia.org/wiki/Season_of_birth

 I'd say the effects are variable. I'll give a couple examples.

Delora was raised in Hawaii and consequently, Ohio and its cold weather make her depressive because she is not used to it. Some people are not happy in the winter here. I personally  mind because I was born in a blizzard and lived in Ohio my whole life. The fall makes me sentimental and happy. SC gets more intense in the fall.