Idiom: 'Get a life'

[Tom]

Hi

Could you please tell me the meaning and use of the following idiom? I could not find it on Google!

Get a life

Tom

[Pamela]

Hi Tom
I know that get a life is an American slang expression. Maybe others will give you more information on this.

Ex.You are such a twit. Get a life!

[Conchita]

Get a life! INFORMAL
something you say to a boring person when you want them to do more exciting things:
Don't tell me you're cleaning the house on a Saturday night? Get a life, Hannah!

(Cambridge Advanced Learner's Dictionary)

get a life
1. to have fun. With the time you save, you could learn Italian, paint your basement, even get a life.
2. to do something different. He needs to leave home and get a job - in short, he needs to get a life.Usage notes: often used as an instruction to someone who complains: They're always telling me I shouldn't make fun of people, and I just tell them, "Grow up, you know, get a life."

(TheFreeDictionary)

[Pamela]

I also found another meaning of this expression that corresponds to Conchita's.

[Yankee]

Hi Tom

To me, "Get a life" is most often used in a negative, critical or sarcastic sense. Here is the Wikipedia explanation:
http://en.wikipedia.org/wiki/Get_a_life

Amy

[Prezbucky]

...like when I don't feel like coughing up $80 to take the woman out on the town...

"Tom, I want to go out. Take me out, now!"

"No. I'm trying to save some money."

"You need to get a life!"

hehe
_________________
Billie Jean is not my lover. Hee.

[Alan]

As I said earlier today:

Hi,

[Pond969]

I don't see this as a slang expression or an idiom since its meaning is directly derived from the component words... as long, that is, as 'life' is understod to mean a 'meaningful' life (which seems to be neccessarily implied anyway).