The most common async/await pitfall
The .NET async/await pattern for writing non-blocking code is great, but there's lots of way you can get into trouble with it. In many cases, either the compiler or a static analysis tool like Resharper can tell you that you have forgotton something.
ASP.NET MVC Partial View gotcha
In our large MVC project, we have quite often decomposed views into pages containing partial views. For example, if a profile widget is used on multiple different pages, then it becomes a partial view (MiniProfile.cshtml). We would then have the model object used by the partial view as a child property on the model object of the main view. For example: