With so many of the tools we use nowadays built upon web services, you can end up working in a confusing array of browser windows, and endless tabs. This can get pretty frustrating. Luckily, if you happen to have a preference for stand-alone apps, there are a couple of simple solutions that allow you to turn any website into exactly that. What you end up with are essentially simple web wrappers, in effect single use browser sessions. 
Of the two solutions I know, the first and easier option is to pick up an app called Fluid, for US$5. Using the app is simple, you enter the URL of the web service in question, give the app a name and you’re away. Fluid has some rudimentary settings you can tweak from within the single-use browser it creates, but there is only one that most people will care about. If you are creating a Fluid App for a web service, and you want to keep yourself logged in to that website, then you will need to enable cookies in the security settings.
The second way to do this is to use a clever little utility called Nativefier. Not everyone will feel quite as comfortable with this option as it requires you to use the terminal, but it is still pretty simple in the end. You will need to have Node.js installed, which can be installed with the Node Installer or with the Homebrew package manager if you are that deep in the weeds. Once you have Node, then it is a simple matter of using a couple of vefry basic terminal commands. The first is to install the Nativefier app itself, and the second is to have it build your stand-alone app. I believe anybody can handle entering a couple of simple commands that look like this:
npm install nativefier -g nativefier --name "App Name" "http://example.com"
That really is all it takes. The result with Nativefier is a clean, and responsive stand-alone app. As far as choosing between the two options, it depends both on what you want to use the app for, and whether or not you are comfortable running a command in the terminal . Myself, I use fluid for running this website on Squarespace, because I want a stand-alone app, but I need the tabs that a browser instance gives me. On the other hand, I much prefer Nativefier for apps that don’t require tabs.