It can be generational - I was treated that way by my mum, and yes it upset me and really affected me - but then my mum and step dad would then lay into me and tease me for being 'too sensitive'. Family members didn't want to fall out with them so didn't call them out, except one who did, and relations were frosty for years afterwards - of course all my fault as well. So I just kept my gob shut and put up with it.
This went on into my late twenties after I'd had my daughter and I was following the exact same pattern because a) it was normal to me even though I knew how it made me feel, I just thought I was over sensitive and weird, and B) I didn't want my daughter to become the 'spoiled brat' that I apparently had become because they considered they were too easy on me and that was my problem.
I realised one day, all of a sudden, that I was heading towards the same relationship with my daughter as my mum has with me. And that children don't become spoiled because you're nice to them now and again, understanding and compassionate.
The clarity came when I was cut off as punishment by my parents, there was a "Well if you don't like how we treat you, you know what you can do" convinced that I needed them so would back down as usual, I didn't back down, picked up my coat and daughter and left.
And that's the day it changed. I never wanted her to feel about me how I felt about my mum. I didn't want her to feel how I felt. And out of that situation for a while (as well as showing my parents that in order to be in our lives the least I would accept was being treated decently) I suddenly saw it all for what it was.
I have a great relationship with my DD now, she's 21 and in university, from home at the moment, we are close, share a lot a talk to each other when we're getting pissed off at each other.
It's really sad when children are treated like this, but sometimes it's so entrenched that you can't see it. I'm just glad I saw it and changed before it was too late.