Sure, it's in the title of the show, so what else did we expect? It's not just Alison who is a major liar, though — all five of the friends have told a fib or two in their day, but Alison turned lying into an art form. For instance, one of the bogus lies Alison tells is that Toby Cavanaugh (Keegan Allen) has been spying on her, and she has her minions throw a stink bomb into his garage as revenge. Toby's stepsister Jenna Marshall (Tammin Sursok) ends up getting blinded in the accident, as a firecracker was thrown into the garage and not a stink bomb. The fact of the matter is that Toby was never spying on anyone, and Alison's lie cost someone their vision. Naturally, she then lied to others outside the circle on whose idea it was to set off the stink bomb, and things got worse.
Additionally, Alison and high school teacher Ezra Fitz (Ian Harding) had a brief fling when she was 15 and he was around 21 years old. Of course, she lied about her age, saying she was older and putting Ezra in a dangerous position, but we're not here to make excuses for the creepy English teacher. She also hid the relationship from her friends, and Aria ended up dating her teacher later on.
Let's also not forget that Alison hid for years, as friends and family presumed her to be dead. The girls were taunted by several different "A's," and a few even had brushes with death. It would have been so easy for Alison to just come forward and admit that she was alive, and it would have saved her friends a whole heck of a lot of hurt, but what fun would that have been? Pretty Little Liars probably never would have existed without Alison's lies, but that doesn't make them excusable!
