If filament is too close to each other, the nozzle can “drag” the print instead of having the filament flow smoothly out of the extruder. This can cause a number of problems, including:
1) Chewing up the print bed due to friction between the nozzle and bed.
2) Obstructed airflow, which can cause overheating and inaccuracy in your prints.
3) Fragile prints that may be more easily damaged.