diff --git a/core/dbt/flags.py b/core/dbt/flags.py
index 99de7e28ba3..8f1630e5c40 100644
--- a/core/dbt/flags.py
+++ b/core/dbt/flags.py
@@ -25,7 +25,9 @@
 SEND_ANONYMOUS_USAGE_STATS = None
 PRINTER_WIDTH = None
 
-# Global CLI defaults
+# Global CLI defaults. These flags are set from three places:
+# CLI args, environment variables, and user_config (profiles.yml).
+# Environment variables use the pattern 'DBT_{flag name}', like DBT_PROFILES_DIR
 flag_defaults = {
     "USE_EXPERIMENTAL_PARSER": False,
     "WARN_ERROR": False,
@@ -106,6 +108,7 @@ def get_flag_value(flag, args, user_config):
     lc_flag = flag.lower()
     flag_value = getattr(args, lc_flag, None)
     if flag_value is None:
+        # Environment variables use pattern 'DBT_{flag name}'
         env_flag = f"DBT_{flag}"
         env_value = os.getenv(env_flag)
         if env_value is not None:
diff --git a/core/dbt/main.py b/core/dbt/main.py
index cf1cba648ba..89d00fe4df1 100644
--- a/core/dbt/main.py
+++ b/core/dbt/main.py
@@ -385,6 +385,7 @@ def _build_build_subparser(subparsers, base_subparser):
     sub.add_argument(
         '-x',
         '--fail-fast',
+        dest='sub_fail_fast',
         action='store_true',
         help='''
         Stop execution upon a first failure.
@@ -488,6 +489,7 @@ def _build_run_subparser(subparsers, base_subparser):
     run_sub.add_argument(
         '-x',
         '--fail-fast',
+        dest='sub_fail_fast',
         action='store_true',
         help='''
         Stop execution upon a first failure.
@@ -706,6 +708,7 @@ def _build_test_subparser(subparsers, base_subparser):
     sub.add_argument(
         '-x',
         '--fail-fast',
+        dest='sub_fail_fast',
         action='store_true',
         help='''
         Stop execution upon a first test failure.
@@ -1038,6 +1041,16 @@ def parse_args(args, cls=DBTArgumentParser):
         '''
     )
 
+    p.add_argument(
+        '-x',
+        '--fail-fast',
+        dest='fail_fast',
+        action='store_true',
+        help='''
+        Stop execution upon a first failure.
+        '''
+    )
+
     subs = p.add_subparsers(title="Available sub-commands")
 
     base_subparser = _build_base_subparser()
@@ -1086,13 +1099,23 @@ def parse_args(args, cls=DBTArgumentParser):
     parsed = p.parse_args(args)
 
     # profiles_dir is set before subcommands and after, so normalize
-    sub_profiles_dir = getattr(parsed, 'sub_profiles_dir', None)
-    profiles_dir = sub_profiles_dir if sub_profiles_dir else parsed.profiles_dir
-    parsed.profiles_dir = os.path.abspath(profiles_dir)
+    if hasattr(parsed, 'sub_profiles_dir'):
+        if parsed.sub_profiles_dir is not None:
+            parsed.profiles_dir = parsed.sub_profiles_dir
+            parsed.profiles_dir = os.path.abspath(parsed.profiles_dir)
+        delattr(parsed, 'sub_profiles_dir')
 
     # version_check is set before subcommands and after, so normalize
-    if getattr(parsed, 'sub_version_check', None) is False:
-        parsed.version_check = False
+    if hasattr(parsed, 'sub_version_check'):
+        if parsed.sub_version_check is not None:
+            parsed.version_check = False
+        delattr(parsed, 'sub_version_check')
+
+    # fail_fast is set before subcommands and after, so normalize
+    if hasattr(parsed, 'sub_fail_fast'):
+        if parsed.sub_fail_fast is not None:
+            parsed.fail_fast = True
+        delattr(parsed, 'sub_fail_fast')
 
     if getattr(parsed, 'project_dir', None) is not None:
         expanded_user = os.path.expanduser(parsed.project_dir)