Answer:
The environment influences people in so many ways, it would be impossible to list all of them. However I will try to give some examples, I’m talking from the top of my head here so feel free to expand or correct me.
For starters… what would people be without the environment? Non existent. Everything we have in our lives is because of our surroundings. In the modern age being able to travel to different places and international trade definitely expand our scope, but still there are plenty of things you could only see or get at particular places.
Explanation:
When we talk about culture and groups of people we have to talk about food. Regardless of where you are on the globe people have a certain relationship with food and hold it at great value. The environment in which the people are dictates the types of food they have access too. That’s why island nations (or coastal regions) focus on fish in their cuisine - Japan is a prime example of food becoming a national staple; countries with warmer climates have fresh fruits and vegetables in their diet while people in colder climates historically rely on fatty meats, fish and root vegetables like potatoes.
The environment determines what kind of clothes we need or don’t need depending on the seasons and temperatures, and also back in the day in the day it determined the animals from which we could acquire fur for clothes (also primary meat people might eat as well as predators to be aware of).
On the topic of clothes and art forms, the environment to some extent determines the predominant colors people use as they tend to mimic what they see around them. Here is a stereotypical example of the brightly colored Hawaiian shirts on the islands full of flowers compared to the muted grayish-blue/brown coats you would encounter in gloomy London (of course those things apply less nowadays that’s why I’m using stereotypes).
The environment shapes architecture - from the materials people use to build (wood, stone, brick etc), to the locations they chose - settlements are usually built close to a water source (river, lake, sea) or close to some other type of valuable resource - forest, gold, marble etc. It also can dictate the style of the buildings - in a desert you want something made of a light stone to reflect sunlight, that is open an airy so you don’t melt to death in it. Needless to say when you look at North Africa, the Middle East, desert US states those elements are visible in the buildings. Lack of space is also a factor - if you take Hong Kong for example, buildings there are very narrow but extremely tall, it’s because there’s not a lot of land to go around so they’ve opted for stacking. Same to an extent in Japan with rice terraces being and example of agricultural stacking.
Also high ground is a military advantage (maybe not so much today with satellites, camouflage is a better option) and at least in the past military compounds, castles and fortresses were built on hills, cliffs and mountains (as an example take Scottish castles - Edinburgh, Stirling, Dunnottar). Our surroundings and what we are used to influence our mindset - in a military point of view overestimating his troops in winter conditions cost Hitler the invasion of the Soviet Union. Germans suffered great losses in the cold, while the Soviets thrived in it, which is understandable as they have very severe winters. The same with the British freaking out over the tiny bit of snow while Canadians live literally buried in it and it’s not big deal.
In Nordic countries for example, the lack of sunlight in the winter months triggers depressions and lethargy, seasonal affective disorder they call it and the more north you live, the more prone you are to it. At the same time, being in a warm climate closer to the equator affects daily life in a different way - people spend more time outdoors because the weather is more often nice, they have outdoor restaurants, cinemas, markets, they would stay out later, they would walk outside more, kids would have more places for outdoor activities and so on.