There are a few things I would like to say about this story...
First, "customer" says he bought a NEW tractor and later called it a bad lemon floor model. Well, first he would have gotten a discount if it was indeed a floor model or had been previously sent out for repair. Also if it was indeed a floor model or reconditioned, there would only be a 30 day warranty on it.
Second, just because something says lifetime guarranty or 2 year guarranty, please please read your paperwork! There are many reasons that a company wont stand by that guarranty. Especially if they believe you have used and abused the item in question.
Third, going into a store and yelling or getting angry at a store associate is not going to help matters. If you calmly state what your problem is, you are more likely to recieve help on such matters. Also, dont make it personal (ex, you sold me this junk, you did this or that...) trust me, it wont help you or make anyone else want to help you.
And my last comment, the reason the store manager was giving you "all kinds of 800#'s" is because that is what he is supposed to do, he is supposed to put you in contact with the right people who can help you. If he was giving you corporate numbers that is because your mower wasnt covered by warranty and it was over the 30 return policy and there was simply nothing he could do. There are company rules for those kind of things. My suggestion, take those numbers he gave you and call them! Find out some more information about why the mower isnt covered.. if it is fact a "lemon" then you tell the district manager or someone higher up and your problem will get taken care of. Dont belittle them or the company they work for as most Home Depot employees tend to bleed orange and take it very personally. I hope this helps you.