You lost $4000 because you were scammed by a fake book publishing company. You are really angry at yourself for getting tricked by it. You say to a friend:
I can't believe I fell for that.
publishing, regret, scam, simple past, tricks, 日本語サポート 
You wrote a book, and sent it out to lots of different publishers. One publisher agreed to print it, but said that you had to pay $4,000 to cover publishing fees. You were excited to have your book published so you gave them the money, but now you've only sold a few copies of your book. You regret paying the company, so you tell your friend:
In retrospect, I probably should have known it was a scam.
Your wife played a trick on you by saying that she hadn't paid your mortgage, when in fact she had. You really believed that she hadn't paid it, and you were worried. After she tells you the truth, you laugh and say:
You had me there for a second.
Your wife told you a little lie as a joke, but immediately told you the truth. She said that she hadn't paid the mortgage, when she actually had. You're telling your wife's sister about this the next day, and you say:
She played a little trick on me last yesterday.
Your husband asks you if you sent your mortgage payment to the bank. You did, but you want to play a trick on him. You say "Oh not, I totally forgot!" When he starts to look worried, you say:
Just kidding!
