I agree on the extended warranty issue at Harbor Freight. Not worth the money, but they sure try to sell it to you!
Last week I was there and bought their 20 ton hydraulic press along with a few other odds and ends. The young fellow at checkout asked if I would be interested in the extended warranty, to which I politely responded "No, thank you". He tried again and again I replied "No, thank you" but with a little bit more emphasis. He decided to try a third time, but I cut him off with "Young man, I told you twice, NO, and I was polite about it. If I have to tell you a third time, you will have to take all this stuff and put it back on the shelf, and I will spend my money elsewhere."
You guessed it, he gave up.