Honest advisors

Marichi says to King Ravan in Ramayan:

सुलभः पुरुषः राजन् सततं प्रियवादिनः।
अप्रियस्य तु पथ्यस्य श्रोता वक्ता च दुर्लभः॥

Which means, O' gracious King, you will easily find people who always speak sweetly. But, rare are...the speakers and listeners........of bitter but honest advice that shows the right path.

These words are said many times, such as Maarichi saying it to Ravan and Vidur saying it to Dhritrashtra. Maarichi later transformed into the deceitful golden deer that took Ram away from Panchvati, in Ramayan. Vidur was an advisor to King Dhritrashtra, the father of Kauravas in Mahabharat.