Why is it difficult to face the last 6 years of Rahu Mahadasha?

As per Vedic Astrology, Rahu Mahadasha lasts for 18 years

Rahu is the shadow of Saturn on the Moon. It is considered the North Node

Now coming to the question – I am not sure if the first, middle or last six can be considered good, bad or ugly

We need to remember that towards to end of Rahu Mahadasha – there is Moon and Mars Antardasha

Moon represents our emotions

Mars represents our energy and will power

Considering this, we need to multiply the planets representation with Rahu’s nature (expand and deviate us from the path)

So, accordingly, we can see

• Rahu Mahadasha and Moon Antardasha
  • Impact: Lack of Happiness, Constantly chattering mind, Poor Sleep Quality
• Rahu Mahadasha and Mars Antardasha
  • Impact: Lack of Will power, Pursuit of non-fruitful endeavors

Hope this gives you an idea

While having said this, the placement of Rahu in the chart and its aspects will be important

God Bless!