It used to be a standard theme in science fiction: a ship is sent out to colonize a new planet, the survey crew makes positive findings, and once the colonists awaken from cryogenic sleep and start living on the planet, they find out what's actually wrong with it. Often it's a bit simplistic: the orbit turns out to be highly eliptical and seasons are drastic and long, or they wind up in a highly volcanized area, or something else a survey crew should have caught before colonization.
I have a planet to describe for you. Imagine, if you will, that the choice is yours whether to wake the colonists and set down on it. You start reading the survey report.
The basics work for humans. Gravity is OK, the period of rotation is comfortable, the air is within breathable parameters, and the sun is the right kind, a "G". It is noted in the report that it does emit radiation that can cause severe burning with overexposure, causes blindness over a long number of years, and long years of exposure wrinkle and toughen the skin, even causing cancer in some number of individuals. There are a few areas with comfortable temperatures, but most have such extremes of hot or cold or both that you need to be protected from it.
The planet is not stable. Vast areas are prone to earthquakes on a frequent basis, mostly minor but some severe, and volcanoes are currently active in several areas. There are some giant calderas, with no estimate of when they might become active and destroy most of a large continent. Most of the surface is water, but not drinkable. Where there is drinkable water, the distribution is irregular. Vast areas receive no rainfall, while others receive heavy rains daily. Some areas have rains varying by season. Floods and droughts are common. Significant amounts of water are tied up in polar glaciers, more in clouds which can produce massive storms coupled with extremely strong winds. Lightning is always present somewhere. If you didn't put up satellites, you have no way of establishing patterns and predicting extreme weather events.
There are a lot of ways the planet itself can kill you. Even more dangerous, however, are the many life forms inhabiting it. The good news is that many of the proteins are compatible: you can eat them safely. Plants have a variety of physical defenses against you, however, including toxins that can give you a rash or indigestion in the mildest cases, or downright kill you, sometimes slowly, with anything from an allergy to a neurotoxin. Some manufacture chemicals which are both harmful and addictive. They also can scratch or poke though unprotected skin, or just tangle around your feet as you try to pass. There are even species of flora which lure, trap, and consume fauna. It will take years, if not generations, to sort them all out.
Millions of species of fauna present their own challenges. Some can be eaten, provided you can catch and kill them. Some will be tasty, others merely edible. All will be hungry. Some will do their best to eat your food supplies before you do. Some will do their best to eat you: compatible proteins work both ways. Yes, there are many kinds of formidable predators, some of which will even cooperate and hunt you in packs. They come in both nocturnal and diurnal varieties, so you will need to rig some kind of protection before you can go to sleep safely. They came in all kinds of strengths and sizes too, and some can even fly. Others will burrow under or chew through your defenses. Even those deemed harmless can become aggressive in defending their territory or families. Some may merely defend themselves with a pharmacopeia of poisons, whether they inject them, coat themselves for skin contact, or keep them in their tissues so you'll never eat more than one.
Insects will be relentless in pursuit of you and yours. Some bite, sting, chew your clothing, housing, ruin your foods, spread microbes. And speaking of microbes, if the proteins are compatible, the microbes will be too. There will be varieties to kill or spoil or sicken everything. Every piece of equipment, clothing, shelter, food, even every bit of yourselves could be vulnerable. Even the normally harmless can trigger an allergy that can become life threatening.
Every bit of life on that planet is busy competing with every other one while defending itself. If you land there, you will have to be constantly on alert to find and take your place among them to survive, much less hope to thrive. So would you stop there? Would you?
Would it make a difference if I told you you're already here?