Bhagavad Gita, Chapter 16, Verse 23

He who, setting aside the ordinance of the Shâstra, acts under the impulse of desire, attains not to perfection, nor happiness, nor the Goal Supreme.

A real, specific warning is given here about ignoring guidance entirely and just following impulse.

Krishna names the actual cost of that approach directly, no perfection, no real happiness, no supreme goal. Real consequences are attached to real disregard.