In the wake of new trends and the paradigm shift to Responsive Web design, I've seen a lot of websites responsive.

However with this adoption and implementation comes what I believe every designer shouldn't take lightly.
UI's should be given a Mobile-First attention during. psd or .png to html conversion. Images should be made responsive too, text should be css-padded or content holders css-margined properly for an enjoyable user experience using media queries.
Zurb and Twitter Bootstrap makes this possible in a breeze.

You know what is truly awry is a semi-responsive website made out of either negligence or improper testing.
My definition of semi responsive website is a "website beautifully implemented but displays not-so-well on small devices".

Testing is using Chrome or Firefox browser smallest window-view size and stretching by various screen resolution to test your UI appearance.
If using any CMS ensure your theme displays readable content and images without constraints for visitors and readers.
Using Firebug isn't enough, a quick reference to the CMS documentation or community forum will help this process of customizing and users will love the experience.

Biggest culprits of semi-responsive pages are blogs and gossip website curated in some kinda hurry. I don't wanna make references but I see alotta popular blogs in Nigeria and India suffering from semi-responsive implementations.

That said, great designs have been implemented by so many great designers and making responsive UIs will always require some trade-offs and negligence. E.g Some Internet Explorer versions will always be ignored at some point as their compliance standard/model is different.

Today "Content is King" does not only hold for the text but it means a proper layout of any presentation published.