A CRJ200 Captain reported loosing situational awareness after starting his taxi at DEN and taking an incorrect taxiway even though he had been there and followed the route hundreds of times previously.

Narrative

Taxied clear of 34R and started to taxi on Taxiway 'F.' First Officer contacted Ground Control who cleared us 'F; Z; G; BS.' First Officer read back clearance. I then said the clearance out loud as well. We identified 'Z' and turn left but just continued on 'Z' instead of making the immediately right onto 'G.' As we continued to taxi on 'Z;' we noticed and the Controller noticed that we didn't make the turn onto 'G.' The Controller spoke up first and said 'Air Carrier 123; I meant for you to taxi the other way. Contact ground on 127.85.' We contacted Ground and we were cleared Z; L; BS. Personally I lost my situation awareness. When I heard the clearance; I pictured the second route in my head even though I said the correct route back to the First Officer but saw the second route in my head and made the second route happen. I had my 10-9 out but couldn't refer to it immediately because I was taxiing; besides I'd been to this airport hundreds of times; right? I knew DEN was gearing up for snow and I figured they were sending us east so that we wouldn't conflict with westbound traffic. I even mentioned that that was a strange clearance. The First Officer must have thought the same thing because he never said anything as it happened. This is a good wake-up call yet again; that even under the most simple of circumstances; you really have to remain diligent and stick to the things we have implemented at our air carrier. Conservative taxi; confirm routes; use your 10-9; take nothing for granted; write down clearances; speak up when/if you think something is not right; stay in the game all the way to master switch off.