You’re just going to have to find out which are the nice ones and vice versa.
There are a number of different creatures in Starbound, some of which are friendly, others are not so.
Each new planet you find will look different to the last, and that might be shown with its inhabitants. After long enough you won’t need to worry about finding new resources, and you’ll end up just enjoying the scenery. Some worlds might have everything you need, whereas others might not have any at all. Each and every single one has something new and unique to enjoy/appreciate. Throughout your explorations, you can pick and choose many different randomly-generated worlds to explore. Not everything is easy to acquire and that’s going to take some exploration, but that’s where the fun comes in. As you explore and scavenge from different planets and take their resources, you can build up your own base and all the items you could ever need. Starbound is effectively Terraria (2D Minecraft as some would call it) but with an accent on sci-fi. By any chance, have you ever played Terraria? Well, if the answer is yes then you should know exactly what to expect from Starbound.