"i guess" is a phrase that can be used in response to almost any situation or comment. its versatility is clearly its strongest asset. popular uses include expressing disdain for something or someone, expressing uncertainty or confusion, expressing the irony and absurdity of a situation, expressing sarcasm, or expressing apathy towards something or someone.
-disdain for something or someone:
Jenny: Actually, you're not invited. Sorry, but, really, I don't want to have any losers like you at my party.
Jim (as she walks away): I guess...
-uncertainty or confusion
Barista: Double special ultra low fat soy grande latte or triple super peppermint vente no milk frap with whipped cream?
Joe: I guess...
-irony or absurdity or a situation
Jane (upon seeing her ex boyfriend with HIS new boyfriend): I guess...
Jamie: She's cool, I guess...
-apathy towards something or someone
Jack: So, are you pro-life or pro-choice? Because I really feel that when you analyze both sides of the issue...
John: I guess.
Saying yes to something that you shouldn't even have to waste your time or effort into saying "yes" to.
I guess really means, "yes"
I guess is an answer to a question that a person should already know the answer to before asking the question.
Jane: Do you race your car?
Mike: I guess..
Jane: Did you go to the store?
Mike: (true meaning) What do you think you stupid idiot? (Give me secks!)
It's a phrase that stupid geeks use at the end of each sentence because they don't want to look RUDE, or anything even though they are!