Tunnel Vision and Selective Attention (Jakob Nielsen's Alertbox).
Design is hard. As much of a blanket statement that is, being a good designer is not something that happens overnight and often results in issues outlined in this Nielsen Alertbox. I know that I miss things on sites all the time when reviewing them with clients simply because the design doesn’t facilitate my noticing the element being referenced in conversation. Many times I’ve missed design elements within an interface highly regarded as excellent design due to my ‘tunnel vision’ which begs the question of tunnel vision being subjective. I like the subject of this Alertbox, and I enjoy the conclusion as well.