I have two
First one is my SIL (husband's sister)
She means well, but we're very different people, and she can be brash and overbearing. We're constantly working on maintaining boundaries for her, as otherwise she'd stamp all over them.
When I had my baby, she arrived unannounced a few days after we came home. This coincided with the community midwife visiting, and instead of making her excuses and leaving, SIL sat there and listened as the midwife asked me all the usual questions, some of which were extremely personal. Meanwhile SIL's toddler DC was trashing the house. In hindsight I wish I'd said something, but I was so weak and exhausted. The midwife should have as well, she kept glancing over at sil with that sort of expectant "time to fuck off now" look but sil has the hide of a rhino. Midwife was younger than I was at the time and I think she was a bit intimidated too. Even sometimes now I think back to it and it infuriates me!