My job requires I dress in coat or tie or so-called "business casual".  In either case I need a good basic dress sock.  These fit the bill.  They are comfortable, durable, and so far, hold up well in the wash.  The biggest problem with black socks is they tend to fade over time and become more gray than black.  I haven't had these long enough to know how quickly they will fade, but based on the couple of washings so far, I'm optimistic.