I shouldn't have to tell you that there's a huge hatred by the majority of adults against the use of the word "like". My mother vigorously corrects me every single time I say it (EVEN IF I'm saying it in its "proper" context - "She danced like a ballerina"), and every teacher I know has gone on rants about how horrible it is, it's contributing to the (imaginary) "decline of proper English" among young people, how it's making the word "said" obsolete, etc. Dozens upon dozens of articles have been written on it, so I'm not even going to link to any specific one. Because I have the same response to all of them:
Get over it, people.
Introducing a familiar word into a new context in a language does not indicate a "decline" in that language. (I bet these people who are so vehemently opposed to this word would have been outraged back when "you" started to become singular...)
Moreover, here's a surprise: People use this word this way because it is useful. Everyone opposing the word points to the fact that you should say "said" instead - but "like" does far more than that.
"I was like, 'I would never do that.'"
"She was like, shocked."
"They were like," *shrug*
"I'm like, they wouldn't actually go that far..."
"Like" is used not just as a substitute for "said", or as a sentence "filler". It is used in most cases to indicate a general form of expression - emotion, action, words, appearance, and even thought. It is incredibly useful - many of the cases in which "like" is now used would be hard to word otherwise. And again, I keep coming back to this point - it is getting the same point across. In perhaps even a better way, you still understand what is being said.
So, I'm like, this word is good. Let's stick with it until something better begins to be accepted.
EDIT: Sofi makes an excellent point in the comments about how helpful the ambiguity of this word can be - when I say "She was like, 'woah'", I am not saying that those were her exact words. Instead, I'm giving a sense of her overall manner as it appeared to me.