Let's be honest, you don't thank the previous dealer when you sell your car. This isn't a personal relationship that involves closure. It's a job that you're leaving for better opportunities. I've seen people stress themselves because they're leaving places like McDonald's.
Understandably, some coworkers become family, and that's great, but we're talking about writing a separation letter to a business in hopes of returning. Keep in mind, there's no special folder marked “2 weeks notice”, I highly doubt any business is keeping a huge backlog of notices just because.
So I ask, what is the obsession with 2 week notices? What does it do for you?