Its a minor nuisance, but its still a nuisance. Everyone once in a while Ill find a new SE site that looks interesting or that Ill have a comment for, but when I go to make the comment, the system asks me to make an account. Generally, its a very small comment and I'm too lazy to make an account for that.
What I don't understand is why I need to make an account every time. They all get linked anyways, so why isn't it just assumed we have an account everywhere?
Edit: For those who think that this is a bad idea because (1) some users don't want to associate with some site, (2) it would ruin site's user statistics or (3) it would spam their communities list, this can be avoided by doing this with a 'copy-on-write' mentality. In other words, you wouldn't actually have an account on the site until you performed your first action. Then an account would be created and linked for you instantly and (more importantly) seamlessly. This means (1) you aren't part of the community unless your actually part of the community, (2) the sites don't get the user statistics until they actually get the user, and (3) you dont see a massive list of communities your part of until you are actually part of those communities.