>>That's normal in any group, though more common in a mixed group where people are less familiar with each other's parameters.<<

Actually a mixed group presents a specific advantage that more... mono-composite (?) groups lack: you know that people are going to disagree and you know that the disagreements are not malicious or character flaws, and you expect to have to work through it.

Someone crowds you / keeps dodging away or flat-out runs and hides? Different proxemics. Someone treats a pet like a child? It's not that they're a raging eccentric, it's just a cultural difference. Mismatch between different 'offer to feed the guest rituals'? Not malice or unfriendliness, and once you learn that it tones down to "whose ettiquite-set are we using today?" Someone drops an n-word or equivalent outside appropriate context, and its probably a misunderstanding which should be cleared up calmly (but it's also fine to be upset or hand the problem off if it smacked into your old emotional injuries).

Basically, there is more of a default effort toward understanding each other and making each other feel safe.