How not to run a marathon:
1. Get sick with flu about 3-1/2 weeks before race, take week off and start taper early.
2. Ease back into training for last few real workouts, realize that from flu that after 35-40 minutes of even light training you feel whipped with no energy.
3. Recover to 90% by weekend before race. Do easy 2 hour bike ride and realize it's good that you didn't completely poop out after 35-40 minutes like in #2 above.
4. Get sick, again, with sinus cold three days before race. Take Zicam, vitamin c and lots of oranges for 2-3 days.
5. Wake up race day feeling so-so, take one last shot of Zicam at 5 am, go to start and sleep in car in 45 degree rain for 2 hours.
6. Start out with your projected pace group based on last 4 months of training, no matter that you've been sick off and on for 3 weeks. Run what feels like an easy first 5k (21 and change), 10k (43 flat) and half (1:36).
7. No matter how easy the first 10-12 miles feel do the right thing and resist the urge to go off the front with others that leave the 3:10 group.
8. Hit the 'wall' at mile 14 when the last 3 weeks catch up to you and the body says, hey, I'm still sick, WTF are you doing running in crappy, windy weather.
9. Spend the next 12 miles doing a slow trot while periodically blowing snot rockets and trying to catch your breath/clear your sinuses. Become unable to keep pace and heart rate up and start to get cold and spend the next two hours shivering.
10. Wait for the 3:20 group to catch up to you, try to hang with them for a mile or two, body again reminds you of being sick and says no way.
11. Repeat #10 with the 3:30 group. Realize that the last long run you did in training was 22 miles of pure hills at a faster pace than what you are trying to run now and that felt easy. Try to use that logic to argue with your body and convince it to keep with the 3:30 runners. Body again says no.
12. Realize you are sick/defeated and are probably doing more harm than good. Think about dnf'ing, but find poor guy cramping that was shooting for a 3 hr race and is now just trying to finish. Shout him words of encouragement as you pass him, then have him do the same to you as he passes you back. Repeat for the final 5-6 miles.
13. Struggle in to a 2:03 second half for a 3:39 run, or about 20-30 minutes slower than planned.
14. Log it as a long training run, be happy with the splits for the first half, move on.
That pretty much sums it up.