While you certainly don't need to explore your entire time at the company, saying thanks and listing some of your accomplishments in the written notice is a good idea.
It has been a pleasure working with you and your team the past (amount of time you've been at the company). This was an incredible opportunity to build my career, and I will always cherish (two or three things you accomplished during this role). The lessons I've learned at (company), including (some skills you've learned at the job), have been valuable.
Thank you very much for the opportunities and support during my time at (company). I wish you and the team success and the best of luck, and hope we can keep in touch.
Sincerely,
(Your name)