At some point, fairly recently, Safari started opening new tabs to the right of the currently open tab, instead of opening them at the end of the tab bar, as nature intended. This means that you have to search for the newly opened tab, instead of just knowing exactly where it is. I can see the point of opening tabs next to the current one, but I don’t like it.
Happily, there’s a way to revert Safari’s behavior to the good old way — the way my grandmother, and her grandmother before her, dealt with their tabs. It’s a simple option inside Safari’s debug menu. Wait? Debug menu?