Traits: Plant Lover/Loner
Lifestyles: N/A
Items/Objects: On or off lot plants
Plan: Loners who you keep busy still eventually need to talk to someone... not anymore!
Results: You gain both social and fun from talking to plants. You don't even need to be a gardener or have a plant on your home lot, and you get a balance of both positive and negative moodlets. The plants are in the open world or almost any lot. You do not have to keep them happy/clean/etc. like minor pets nor relationship panel.
Rating: 8-10/10
Conclusion: What I like about this combo is that you technically don't have to be a loner gardener/harvester, and if you are a loner gardener or flower arranger you get can get positive and negative moodlets (more negative as a flower arranger as you are cutting up/harvesting your friends!).
I'd say this is a 9/10 if you are not planning to use Natural Living Skill but only 8/10 if you are (especially if you are also are a Naturopath, so many plant interactions), because you almost get too many interactions with plants as Plant Lover/Natural Living Skill/Naturopath. However, this combo could be considered a 10/10 for the flexibility factor and possibility of self-sufficiency with the right skills of this combo.
If you do pair with the Natural Living Skill with Plant Lover/Loner, your Sim will be pretty much self-sufficient. So if you like to solo game, collecting and traveling (with or without gardening/harvesting). You really don't need anyone.
