First off....
If it is actual smoke- then yes that is a problem. Since you are alive to post here, I assume it is not smoke filled with carbon monoxide or your engine burning up, but is in fact harmless condensation in the car's A/C system.....
THAT is most likely nothing to worry about.
1) Make sure your air conditioning drain is not plugged up. (do you see a puddle of water under the engine when you park with the A/C on?) You live in SoCal (thank you for posting your location, by the way

) so your A/C gets used a lot. Remember that the job of the A/C is to remove moisture from the air- it does not "cool" the air, per se, it only removes moisture.
2) Make it a habit to turn off your A/C while the blowers are still going strong. Perhaps when you are 2-3 blocks from your destination, you can just press A/C to turn it off while allowing the blowers to still blow cold air for a minute. That will keep the A/C system in better shape than turning the A/C off only when you shut the car down.
3) If you notice a musty smell- then you will have to buy a $15 can of A/C cleaner and run it through.