diff --git a/mocket/decorators/mocketizer.py b/mocket/decorators/mocketizer.py
index 4020d52..fb7c811 100644
--- a/mocket/decorators/mocketizer.py
+++ b/mocket/decorators/mocketizer.py
@@ -15,9 +15,9 @@ def __init__(
         self.instance = instance
         self.truesocket_recording_dir = truesocket_recording_dir
         self.namespace = namespace or str(id(self))
-        MocketMode().STRICT = strict_mode
+        MocketMode.STRICT = strict_mode
         if strict_mode:
-            MocketMode().STRICT_ALLOWED = strict_mode_allowed or []
+            MocketMode.STRICT_ALLOWED = strict_mode_allowed or []
         elif strict_mode_allowed:
             raise ValueError(
                 "Allowed locations are only accepted when STRICT mode is active."
diff --git a/mocket/mode.py b/mocket/mode.py
index e1da795..ac2ca16 100644
--- a/mocket/mode.py
+++ b/mocket/mode.py
@@ -9,7 +9,7 @@
     from typing import NoReturn
 
 
-class MocketMode:
+class _MocketMode:
     __shared_state: ClassVar[dict[str, Any]] = {}
     STRICT: ClassVar = None
     STRICT_ALLOWED: ClassVar = None
@@ -31,7 +31,10 @@ def is_allowed(self, location: str | tuple[str, int]) -> bool:
         return host_allowed or location in self.STRICT_ALLOWED
 
     @staticmethod
-    def raise_not_allowed() -> NoReturn:
+    def raise_not_allowed(
+        address: tuple[str, int] | None = None,
+        data: bytes | None = None,
+    ) -> NoReturn:
         current_entries = [
             (location, "\n    ".join(map(str, entries)))
             for location, entries in Mocket._entries.items()
@@ -39,7 +42,20 @@ def raise_not_allowed() -> NoReturn:
         formatted_entries = "\n".join(
             [f"  {location}:\n    {entries}" for location, entries in current_entries]
         )
-        raise StrictMocketException(
-            "Mocket tried to use the real `socket` module while STRICT mode was active.\n"
-            f"Registered entries:\n{formatted_entries}"
+        msg = (
+            "Mocket tried to use the real `socket` module while STRICT mode was active."
         )
+        if address:
+            host, port = address
+            msg += f"\nAttempted address: {host}:{port}"
+        if data:
+            from mocket.compat import decode_from_bytes
+
+            preview = decode_from_bytes(data).split("\r\n", 1)[0][:200]
+            msg += f"\nSent data: {preview}"
+
+        msg += f"\nRegistered entries:\n{formatted_entries}"
+        raise StrictMocketException(msg)
+
+
+MocketMode = _MocketMode()
diff --git a/mocket/socket.py b/mocket/socket.py
index 496c912..41b25bc 100644
--- a/mocket/socket.py
+++ b/mocket/socket.py
@@ -228,8 +228,8 @@ def recv(self, buffersize: int, flags: int | None = None) -> bytes:
         raise exc
 
     def true_sendall(self, data: bytes, *args: Any, **kwargs: Any) -> bytes:
-        if not MocketMode().is_allowed(self._address):
-            MocketMode.raise_not_allowed()
+        if not MocketMode.is_allowed(self._address):
+            MocketMode.raise_not_allowed(self._address, data)
 
         # try to get the response from recordings
         if Mocket._record_storage:
diff --git a/tests/test_mode.py b/tests/test_mode.py
index ea5905b..bfdb2a7 100644
--- a/tests/test_mode.py
+++ b/tests/test_mode.py
@@ -52,6 +52,8 @@ def test_strict_mode_error_message():
             str(exc_info.value)
             == """
 Mocket tried to use the real `socket` module while STRICT mode was active.
+Attempted address: httpbin.local:80
+Sent data: GET /ip HTTP/1.1
 Registered entries:
   ('httpbin.local', 80):
     Entry(method='GET', schema='http', location=('httpbin.local', 80), path='/user.agent', query='')
@@ -67,5 +69,5 @@ def test_strict_mode_false_with_allowed_hosts():
 @pytest.mark.parametrize("strict_mode_on", (False, True))
 def test_strict_mode_allowed_or_not(strict_mode_on):
     with Mocketizer(strict_mode=strict_mode_on):
-        assert MocketMode().is_allowed("foobar.com") is not strict_mode_on
-        assert MocketMode().is_allowed(("foobar.com", 443)) is not strict_mode_on
+        assert MocketMode.is_allowed("foobar.com") is not strict_mode_on
+        assert MocketMode.is_allowed(("foobar.com", 443)) is not strict_mode_on