One thing that bothers me about “design patterns” is that they don’t always seem to be the best method of solving a design problem. In many cases, patterns are patterns simply because they are popular. This of course is a phenomenon not limited to design (music, for example, is another case in point). However, it becomes particularly frustrating for designers when a sub-optimal pattern then gets in the way of better designs because the pattern becomes something that people expect. Significant modification of the pattern is seen as negative, even if those modifications are demonstrably better. But you can’t do something better by doing the same thing as everyone else.
One example of a design pattern being a poor solution to a problem is the use of pop-up calendars to allow date range selections on form fields. Here’s an example of what I mean. I’ve chosen an example of a single calendar for selecting ranges because I think it illustrates better the points I’m about to make. A more common example is the “from/to” calendar: separate calendars for the “from” date and the “to” date, usually as separate fields on the form.