If you want to delete your account, you are able to anonymise your account yourself. Any posts you have not deleted will remain on the site as will quoted content, but your username showing next to these posts will change and your account details will be removed. To do this, hover over your username in the top bar. Then select 'Customise my TSR' > 'Edit my login settings' where you will see the option to do this. Once you do this you will not be able to get your account back, so please decide carefully!