I've been thinking about this. Stannis was never really given his proper due for his heroic and gallant intervention at the Battle of the Wall. The details of the battle are really only known to the Watch, Stannis' men, the Wildlings, and maybe some Northmen here or there. But the rest of the country never knew how close Westeros was to being completely overrun by a Wildling horde of 100,000. The Watch was on the brink of collapse and was going to lose that battle. Should the wall fall the already war-torn North and ravaged Riverlands at the time of AFFC would have almost certainly been completely overrun. Whose to say how far the Wildlings would have gotten? Gathering deserters, vandals, brigands, and all manner of opportunists to their cause along the way.
Stannis saved Westeros. He saved a country that wouldn't recognize him as the rightful king yet rescued it all the same. And yet the country remains relatively ungrateful. My hope is that his legend will spread south eventually and people will realize just how much he sacrificed for them. Otherwise they deserve the awful Lannister/Tyrell hodge-podge they've got and not the King who fucking cared.