I'll start,
I love my Mum to bits and we have a wonderful relationship, but I had a very serious phobia of needles growing up and I was a very anxious child. She wouldn't tell me I had to have an injection til the very last minute (she would just show up at school or we'd walk into the doctors) and I would have a panic attack. I wish she would have told me a few days before that I was going to have one and why, then I would have been able to make peace with it. It just meant that I couldn't relax when she took us out or at school, it made my phobia worse that she felt she needed to keep me in the dark about it too, like it was something she was also afraid of.
With DD I'm going to avoid doing that and try to be upfront with her from the start.