Slippery slope

Slippery slope refers to a bad situation or habit which, after it has started, is likely to get very much worse.

Some Excerpts:
From TV shows, movies and novels

Sex and the City

Sarah Jessica Parker(Carrie Bradshaw), when out with her friends Kim Cattrall(Samantha Jones), Kristin Davis(Charlotte York), Cynthia Nixon(Miranda Hobbes) had used the phrase “Slippery slope” in Season 2, Episode 13(Games People Play) of Sex and the City as shown below:

From the web:

Following lines are taken directly from the net to show how people use the phrase “slippery slope” in everyday talk.

Tags: Carrie Bradshaw(Sex and the City), Sarah Jessica Parker, Sex & the City