Many yogis, when bad quality of mind comes, the mind resists. This makes the practice difficult.
That’s why we need to use right attitude: bad quality of mind is bad quality of mind; it is not a big problem. Restlessness and sleepiness are just mental states (they have their own nature and arise due to causes and conditions).
If the yogi thinks this way, the resistance subsides and the yogi can continue to be aware.