There are a fair number of options settings. ANSI_NULLS, ARITHABORT, QUOTED_IDENTIFIER, etc. Each session has its own set of configurations. They are initially set based on the user settings system configuration, then the various connection programs (SSMS for example) can override that, then the various SET commands can override that.

Now personally I prefer to keep my settings to the default to eliminate confusion but they do get changed occasionally. Just as a for example, when you generate a script from SSMS it typically includes a bunch of SET ON and SET OFF commands. And if you turn on a setting that was already on, then turn it off and the end, well, your setting has changed unexpectedly. My original intent for this post was to create a stored procedure that would let you save the current settings and restore them. Unfortunately, I ran into a scope problem. I can find the current settings: @@options. I can break down the integer value using a script from here (just in case the post should disappear before this one does here is the code from the article)

DECLARE @options INT
SELECT @options = @@OPTIONS

PRINT @options
IF ( (1 & @options) = 1 ) PRINT 'DISABLE_DEF_CNST_CHK' 
IF ( (2 & @options) = 2 ) PRINT 'IMPLICIT_TRANSACTIONS' 
IF ( (4 & @options) = 4 ) PRINT 'CURSOR_CLOSE_ON_COMMIT' 
IF ( (8 & @options) = 8 ) PRINT 'ANSI_WARNINGS' 
IF ( (16 & @options) = 16 ) PRINT 'ANSI_PADDING' 
IF ( (32 & @options) = 32 ) PRINT 'ANSI_NULLS' 
IF ( (64 & @options) = 64 ) PRINT 'ARITHABORT' 
IF ( (128 & @options) = 128 ) PRINT 'ARITHIGNORE'
IF ( (256 & @options) = 256 ) PRINT 'QUOTED_IDENTIFIER' 
IF ( (512 & @options) = 512 ) PRINT 'NOCOUNT' 
IF ( (1024 & @options) = 1024 ) PRINT 'ANSI_NULL_DFLT_ON' 
IF ( (2048 & @options) = 2048 ) PRINT 'ANSI_NULL_DFLT_OFF' 
IF ( (4096 & @options) = 4096 ) PRINT 'CONCAT_NULL_YIELDS_NULL' 
IF ( (8192 & @options) = 8192 ) PRINT 'NUMERIC_ROUNDABORT' 
IF ( (16384 & @options) = 16384 ) PRINT 'XACT_ABORT'

Then I modified that slightly to restore the options.

DECLARE @options int

-- Set @options to the old value of @@options.

-- https://technet.microsoft.com/en-us/library/ms175103(v=sql.105).aspx
--IF SERVERPROPERTY('ProductVersion') < '10.6'
--	IF ( (1 & @options) = 1)
--		SET DISABLE_DEF_CNST_CHK ON
--	ELSE
--		SET DISABLE_DEF_CNST_CHK OFF
-- https://docs.microsoft.com/en-us/sql/t-sql/statements/set-implicit-transactions-transact-sql
IF ( (2 & @options) = 2)
	SET IMPLICIT_TRANSACTIONS ON
ELSE
	SET IMPLICIT_TRANSACTIONS OFF

-- https://docs.microsoft.com/en-us/sql/t-sql/statements/set-cursor-close-on-commit-transact-sql
IF ( (4 & @options) = 4) 
	SET CURSOR_CLOSE_ON_COMMIT ON
ELSE
	SET CURSOR_CLOSE_ON_COMMIT OFF

-- https://docs.microsoft.com/en-us/sql/t-sql/statements/set-ansi-warnings-transact-sql
IF ( (8 & @options) = 8)
	SET ANSI_WARNINGS ON
ELSE
	SET ANSI_WARNINGS OFF

-- https://docs.microsoft.com/en-us/sql/t-sql/statements/set-ansi-padding-transact-sql
IF ( (16 & @options) = 16)
	SET ANSI_PADDING ON
ELSE
	SET ANSI_PADDING OFF

-- https://docs.microsoft.com/en-us/sql/t-sql/statements/set-ansi-nulls-transact-sql
IF ( (32 & @options) = 32)
	SET ANSI_NULLS ON
ELSE
	SET ANSI_NULLS OFF

-- https://docs.microsoft.com/en-us/sql/t-sql/statements/set-arithabort-transact-sql
IF ( (64 & @options) = 64)
	SET ARITHABORT ON
ELSE
	SET ARITHABORT OFF

-- https://docs.microsoft.com/en-us/sql/t-sql/statements/set-arithignore-transact-sql
IF ( (128 & @options) = 128)
	SET ARITHIGNORE ON
ELSE
	SET ARITHIGNORE OFF

-- https://docs.microsoft.com/en-us/sql/t-sql/statements/set-quoted-identifier-transact-sql
IF ( (256 & @options) = 256) 
	SET QUOTED_IDENTIFIER ON
ELSE
	SET QUOTED_IDENTIFIER OFF

-- https://docs.microsoft.com/en-us/sql/t-sql/statements/set-nocount-transact-sql
IF ( (512 & @options) = 512)
	SET NOCOUNT ON
ELSE
	SET NOCOUNT OFF

-- https://docs.microsoft.com/en-us/sql/t-sql/statements/set-ansi-null-dflt-on-transact-sql
IF ( (1024 & @options) = 1024)
	SET ANSI_NULL_DFLT_ON ON
ELSE
	SET ANSI_NULL_DFLT_ON OFF

-- https://docs.microsoft.com/en-us/sql/t-sql/statements/set-ansi-null-dflt-off-transact-sql
IF ( (2048 & @options) = 2048) 
	SET ANSI_NULL_DFLT_OFF ON
ELSE
	SET ANSI_NULL_DFLT_OFF OFF

-- https://docs.microsoft.com/en-us/sql/t-sql/statements/set-concat-null-yields-null-transact-sql
IF ( (4096 & @options) = 4096) 
	SET CONCAT_NULL_YIELDS_NULL ON
ELSE
	SET CONCAT_NULL_YIELDS_NULL OFF

-- https://docs.microsoft.com/en-us/sql/t-sql/statements/set-numeric-roundabort-transact-sql
IF ( (8192 & @options) = 8192) 
	SET NUMERIC_ROUNDABORT ON
ELSE
	SET NUMERIC_ROUNDABORT OFF

-- https://docs.microsoft.com/en-us/sql/t-sql/statements/set-xact-abort-transact-sql
IF ( (16384 & @options) = 16384) 
	SET XACT_ABORT ON
ELSE
	SET XACT_ABORT OFF

Things were going great until I put the code into a stored procedure. And then as I said above I discovered a scope issue. The scope of the set commands is local. Meaning that while they changed the options, they only changed them within the stored procedure (and presumably any code I called from within the stored procedure). As soon as I came back out of the stored procedure the options were back to where they were.

So basically this post is here to help people (well, really me) find the list of values for the various options. Also in case anyone wants/needs the restore code.