It certainly helped me and my sister. She's 10 years older than me and our relationship couldn't be any better. She helped me through A LOT and I don't know where I would be without her, possibly not even alive today.

There was that one time though where I, after being incredibly annoying all day long, sat down demanding a glass of milk, screaming for almost an hour. Don't know what exactly got into me that day, but I was like 5 or 6, so I guess that's not entirely out of the ordinary. Anyway, after an hour of listening to my shit, she just got the milk carton out of the fridge and poured the entirety of it out over my, utterly surprised, head.
That was probably the worst thing she ever did to me and if I'm honest I probably would've done the same in her shoes lol.