I appreciate honesty above all other attributes. The key is, being honest without destroying the other person. If something a friend has done upsets you, instead of saying "YOU pissed me off, "etc. take responsibility for YOUR own feelings. Use "I" messages instead of :YOU" messages. say, "When you did that, I felt hurt, or upset."
Remember what Shakespere said, "Nothing is good or bad, thinking makes them so."
A good friend is always sensitive to the feelings of others. Not necessarily responsible for them, just sensitive to them.