To many Fantasy RPGs give humans credit for being adaptable. If I wrote an RPG:
"...Humans also get the racial bonus ability: 'Pack Mentality (see Feats section)'...
'Pack Mentality':
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-1 Wisdom
Select any number of arbitrary traits (Table 2.1). Any player or non-player characters having some or all of these traits are considered friendly. Characters not having these traits are considered unfriendly.
+1 to initiate combat against enemies when in group of friendly characters."