I’m not typically a fan of picking traits that will result in canceling other things out or ones that result in major adverse effects; however, there are some that I’d make an exception for.
Terra Firma (or Spaced)
With Terra Firma, you get increased Health and Oxygen (stamina) when on the surface of a planet. The trade-off; however, is decreased Health and Oxygen when in space.
Spaced is the opposite, giving you increased Health and Oxygen when in space and decreasing them when on the surface.
The trade-offs for each of these are a little harsh; however, I believe if you plan on exploring a lot, they provided a solid benefit early on. When first starting the game, it helps if you have increased stamina to help get around planets more quickly. Eventually, as you level up and increase these stats with your skills, you can eventually drop them.
Similar to Terra Firma and Spaced, both Introvert and Extrovert help you save Oxygen when exploring. With the Introvert trait, you’ll use less oxygen when adventuring alone, but more when traveling with other human companions. On the flip side, the Extrovert trait, uses less oxygen when adventuring with human companions but more when alone. Both of these are good traits as oxygen can greatly help you explore more quickly, but picking one or the other will require you to know your preferred playstyle: alone or with others?