Just that, really.
I have 3 siblings and I'm not super close to any of them, but I get along really well with my parents. I'm worried that as my parents age this dynamic may cause issues and am pretty sure they already think I'm the favourite, but it's more so that my parents and I just gel well and have the most similar interests, personalities etc. 2 of my siblings are really close and a bit cliquey with each other (one has been pretty horrible to me in the past but we get along ok now), and one of them definitely doesn't get along well with my parents as she can be very difficult. I do my best with my siblings (one I do get along well with but we're not that close) but I've accepted that we'll probably never be that close.
Anyone else have a similar dynamic in their family?