They wouldn't be scoffing if the Night King's army had access to teleporters just like everybody else
Jon travelled to Hardhome, met the white walkers, travelled back to Castle Black, moved to Winterfell, stayed there, then travelled to Dragonstone. White Walkers were shown walking towards the Wall since the Hardhome episode. They can walk at full pace without resting and yet they couldn't make like 25% of Jon's mileage
D&D shit on that sense of urgency they had created in the Hardhome episode.
Another stupidity: greyscale sub-plot. The legendary uncurable disease was cured by a rookie who grabbed the first book and the instruction was a cartoon with 3 lines of text, the tools needed were the most basic ones.
But overall the Sam/Jim Broadbent dialogues I truly enjoyed to be completely fair. My favourite scenes.