The Most Common and Important Errors Design Professionals Seem to Make

None of us are perfect, even people who design for a living.  Unfortunately, design professionals regularly do the following things, which are oh so very un-good for the people using what they’ve designed:

• Signalling users via the activities that can be done well in a space and through low-quality materials, furnishings, etc., that those users are not respected and that their contributions to their societies are not respected.  Examples:  a workspace where people can’t concentrate and can’t do whatever they’re being paid to do if they can’t focus on the task at hand; a bathroom that begins to age in a very unattractive way as the last tile is being laid.  The silent signals sent by design are reviewed in this article.
• Not thoughtfully curating design options provided and supplying users with too little (the most common situation) or too much control over their lived experiences—or offering oodles of options, none of which line up with what people intend to do in a space.   Designing in the best sorts of environmental control is discussed here.
• Not providing people the basics of what they need to achieve objectives important to them—to eat healthy meals, share good times with family and friends, or do their taxes.  Sure, this point overlaps with the two right above, but it’s so important that it can’t be overemphasized.  Designing to support knowledge work, for example, is reviewed here.
• Throwing people together and hoping that they’ll have great conversations and form wonderful bonds with each other without providing the tools that they need to do so, such as seats of the same sort for all, furniture arrangements that make comfortable levels of eye contact—but not too much or too little—likely, etc. Design that builds interpersonal bonds is covered here. 
• Skimping on opportunities for mental refreshment. For more on how to mentally refresh via design, read these articles.
• Forgetting the fact that humans today still have the same information processing mental apparatus, core goals, etc., as they did when they roamed the savannas and woodlands aeons ago.  Biophilic design (discussed here, and here for instance) incorporates the same sorts of experiences into our lives today that made us comfortable thousands and thousands of generations ago, such as natural materials and soundscapes, just the right levels of visual information (clutter, in layman’s terms), and the kinds of potted plants that calm and boost mental performance, for example.
• Ignoring some sorts of sensory experiences and forgetting that all of the information we cull from our world is combined in our heads to create an overall response to a space or thing.  An example:  adding marble flooring because of how it looks but ignoring how the sounds of shoes walking across it will reverberate.  For more information on how multiple sensory experiences we have combine in our heads, read this article.
• Assuming everyone’s the same and re-using solutions developed for one person or group with another.  How personality, for example, should influence design decisions made,  for example, is covered in this article.