Why do some attributes start with '@' while others done't?

[Wyatt via Digitalmars-d]

On Tuesday, 26 January 2016 at 12:42:37 UTC, w0rp wrote:
> I think we bicker and pontificate about these kinds of issues 
> too much.
>
Yes.  Sorry, got carried away on a tangent.

> Do we want @ for every attribute or not?
>
Yes.

> If you worry about the compiler becoming too complicated, I can 
> assure you it will barely have an impact on compilation speed, 
> and that's all users will care about.
>
Was anyone even concerned about that?

-Wyatt