The comments and/or advice you're giving (and the tone you're using) are the type of things you say to someone before they decide to make the jump if you want them to think long and hard before making a tough decision. When you say it like this to someone who is announcing that his decision is made, you just sound condescending. It doesn't help that you throw in a bunch of advice when you don't even know who he is, what his company/product is about, or what his plan is.