I don't want to keep my account on superuser because this site doesn't suit my taste, how can I delete it?
I have looked into my account but it seems there isn't any option like that, but maybe I am not trying hard enough. Or maybe it can not be deleted?
Its in the help - you contact stackexchange using the contact us link, and set your profile to "delete me".
I'd add the problems you've had might be solved by reading through the help, since your other question and this were both off topic for SU proper
From How can I delete my account?
The Help Center explains that there are two cases:
If your account has interacted with the site by voting or posting, go to the Contact Support page and fill out the form. One of the items in the topics drop-down list is for account deletion.
You can also get to that page via the "contact us" section on the site footer. Please note that account deletion is not instant. It might take several days for your request to be processed.
Due to a known issue, you might want to change your username before deleting the account.
If your account has never voted or posted a question or answer more than once, you should see a self-delete option on your user page next to the edit link:
Either of these procedures cover deleting your account on one specific site.
Content you've posted on the site is owned by you but licensed to Stack Exchange, and you therefore cannot request that it be deleted with your account.
Also of note, we automatically cull old inactive accounts as documented on the blog:
