I guess I don't know my English

Despite encountering this word many times during the course of my work, I only found out today the actual meaning of  it

...and all these while I thought it means a short sentence, a blurb.......OMG, quite the total opposite...dang! I just made a fool of myself in an email sent.

Some people are just so stupid - Part I

Stupid Incident 1
Scenario: Couldn't use my ATM card at Bank ABC despite numerous attempts. Received a sms from the bank later asking me to drop by to have my card checked out. So, the next day, I went to the bank.

Bank Staff 1: Morning Miss, how can I help you?
Me: I can't use my ATM card
Bank Staff 1: So, you want to replace your card?
Me: Ya...I think so.
Bank Staff 1: (issued me a Queue ticket)

At the counter,
Bank Staff 2: Morning, what can I do for you?
Me:  I cannot use my ATM card.
Bank Staff 2: So, you want to replace your card?
Me: Errr...I dunno.  You tell me...
Bank Staff 2:  Excuse me for awhile (she walked to another bank teller to inquire about my card).
Bank Staff 2: Sorry Miss, your card is old card, cannot be used already.
Me: (silently thinking..hmm, I just used this 1 month ago..)
Bank Staff 2: So, you want to replace your card?
Me: (silently saying Oh My God!!).  Might as well la...already cannot used anyway! (silently saying Oh My God!! again)

Stupid Incident 2
Scenario: I wanted to upgrade my broadband to the new high speed package but wasn't sure if my area has coverage. So, I decided to drop in to the nearest TM Point outlet today to ask.

Girl at info counter: Yes?
Me: I want to find out more info about Unifi.
Girl at info counter:Why?
Me: (silently saying Oh My God!!)
Girl at info counter: (gave me queue ticket without waiting for my response)
Me: (silently saying..You are So Stupid!!)