@smattymatty disclaimer: I don't have friends, they all forgot about me when I disappeared into the fediverse.
But I'd say something about moderation. The choice of instance means that you choose who is doing moderation, who can decide to throw you out or to let you stay and the rules around that.
The point of the fediverse is to decentralise the power over moderation, that's why you need to choose an instance.
@eliasr aha, well I followed you so you got a new friend :D
Yeah, the freedom of choice is one of the biggest things I champion about the Fediverse - moderation & shared values is a very important part of that - as is the peace of mind of knowing you can switch instances if one stops following your values.