DD is 2 and has a cousin the same age - dh's sister's daughter Sophie. DH's sister is living temporarily with my inlaws and they do a huge amount of childminding for her. As a consequence they are much closer to Sophie than to dd.
I have accepted this is inevitably the case but their favouritism towards Sophie is becoming a constant irritation. Sophie is very loud and boisterous and they seem to feel irritated by DD's shyness telling her "SOPHIE always gives us a cuddle!" when dd is hesitant around them. Whatever DD does it's always compared to Soohie who always does it better. If Sophie pushes dd around they just laugh and it's left to me to tell her off. I feel tense whenever I'm around them and I'm ashamed to say I find myself wishing dd was more outgoing so they would accept her more. I do stick up for her but it doesn't seem to make any difference. They are now teasing her because she isn't potty trained yet and Sophie is. Sometimes I feel like crying when I see her confused little expression when they're going on.
Why does this bother me so much and how am I meant to deal with it?