Over-drafting
The biggest time sink is filling the grid. Every extra room costs steps, and most filler does nothing for the goal. Draft the spine, then stop.
Ignoring the economy
Skipping gem and step rooms feels efficient until the pool empties at room 30. An unfunded run ends as surely as a lost one.
Chasing rarity
A rare room that fits no route is worse than a common room that solves your problem. Rarity is a hint, not a ranking.
Forgetting clues
Room descriptions are where puzzles live. Skim them and you will re-clear the same wing later with no idea why the door will not open.
Fixing the habit
Before each placement, ask one question: does this room serve the day’s goal? If not, skip it. The room database makes the job of each room obvious at a glance.