Of Troy - the name 'Mara' means bitter in Hebrew, and I think it is related to Myrrh; it's the name Naomi gives herself when she goes back to Israel in the book of Ruth, because she believes the LORD has dealt harshly with her (although the later events show her to be wrong). Here are some other words about myrrh and its symbolism, from a sermon about the gifts the Magi brought Jesus...

It's also interesting to note that the Greek word for myrrh, "smurna", is the same as the name of the city and church which received a letter from the Apostle. Smyrna was the second of the seven churches of Asia that John was instructed to write to in the early chapters of the book of Revelation. This church was distinguished by it being persecuted (Revelation 2:8-11) - they understood the bitterness of being mistreated for the sake of the Gospel.

Myrrh then is brought as a gift to acknowledge the human suffering that Jesus partook of when He came into our world. Why did He refuse the drink? Because He had already drunk it. He had prayed at first that He could be spared the cup, but then He submitted to His father's will and drank it - the bitter cup of His suffering.