diff --git a/main.py b/main.py
index 636c6bf6..46e3618c 100644
--- a/main.py
+++ b/main.py
@@ -19,8 +19,8 @@ import memgpt.humans.humans as humans
 from memgpt.persistence_manager import InMemoryStateManager as persistence_manager
 
 FLAGS = flags.FLAGS
-flags.DEFINE_string("persona", default=personas.DEFAULT, required=False, help="Specify persona")
-flags.DEFINE_string("human", default=humans.DEFAULT, required=False, help="Specify human")
+flags.DEFINE_string("persona", default=None, required=False, help="Specify persona")
+flags.DEFINE_string("human", default=None, required=False, help="Specify human")
 flags.DEFINE_string("model", default=constants.DEFAULT_MEMGPT_MODEL, required=False, help="Specify the LLM model")
 flags.DEFINE_boolean("first", default=False, required=False, help="Use -first to send the first message in the sequence")
 flags.DEFINE_boolean("debug", default=False, required=False, help="Use -debug to enable debugging output")
@@ -43,7 +43,14 @@ async def main():
         logging.getLogger().setLevel(logging.DEBUG)
     print("Running... [exit by typing 'exit']")
 
-    memgpt_agent = presets.use_preset(presets.DEFAULT, FLAGS.model, personas.get_persona_text(FLAGS.persona), humans.get_human_text(), interface, persistence_manager())
+    if FLAGS.model != constants.DEFAULT_MEMGPT_MODEL:
+        print(f"Warning - you are running MemGPT with {FLAGS.model}, which is not officially supported (yet). Expect bugs!")
+
+    # Moved defaults out of FLAGS so that we can dynamically select the default persona based on model
+    chosen_human = FLAGS.human if FLAGS.human is not None else humans.DEFAULT
+    chosen_persona = FLAGS.persona if FLAGS.persona is not None else (personas.GPT35_DEFAULT if 'gpt-3.5' in flags.MODEL else personas.DEFAULT)
+
+    memgpt_agent = presets.use_preset(presets.DEFAULT, FLAGS.model, personas.get_persona_text(chosen_persona), humans.get_human_text(chosen_human), interface, persistence_manager())
     print_messages = interface.print_messages
     await print_messages(memgpt_agent.messages)
 
diff --git a/memgpt/personas/personas.py b/memgpt/personas/personas.py
index 50576493..a0d1ffb5 100644
--- a/memgpt/personas/personas.py
+++ b/memgpt/personas/personas.py
@@ -1,7 +1,7 @@
 import os
 
 DEFAULT = 'sam'
-GPT35_DEFAULT = 'sam'
+GPT35_DEFAULT = 'sam_simple_pov_gpt35'
 
 
 def get_persona_text(key=DEFAULT):