In Greedfall you have a parameter on which you judge your relationship with other people in the game. It is called reputation. Greedfall reputation has two types, one for Factions and one for personal reputation with Companions.
Keeping an eye on these parameters and working to gain more and more is a very beneficial thing. You will get rewarded for your reputation points.
Faction reputation is like your relationship with the whole group of people from that faction while companion relationship is your personal relationship with some particular companion.
You will have notifications on your screen whenever certain events increase or decrease the influence on a certain faction.
Completing side quests when you are with a faction and some dialogue choices help you gain reputation with factions.
This reputation helps you gain some rewards at each new tier. When you reach a nice reputation with a certain faction you will get some specific rewards specialized by that faction.
Like with the Coin Guard you will get Hammer of the Forgotten Gods, a gold rarity weapon, and a green cape. These rewards can be very helpful in your main quest if you get them early in the game.
It also works in the same way as the faction reputation. When you work with a certain companion, you will have to complete some specific quests that are going to improve your relationship with that particular companion.
Companions do not give you certain rewards like factions but they will offer you even more quests and completing them will give you more experience early on in the game that will be helpful.
Increasing reputation with companions and improving your relationship with them also open up more opportunities such as the ability to romance a certain companion.