This is an extended Haiku about those people in our lives who we know are bad for us, but, we keep around anyway. Just because a person is hazardous to our life, doesn't mean that it is always easy to simply remove the head of the serpant; sometimes, that snake in the grass becomes the snake in the glass, and is kept as a pet.
Sidenote: I used 5-7-5 syllables in this one, because, I realize I may have been off with 5-8-5; although, I could always add that structure to my style of extending Haikus.