balthiersbit

You can set your sims to either follow your commands fully or let them have a certain amount of self control, ie if they need the bathroom they will go themselves without your command.

If you have a sim on another lot then your other sim may show up from time to time. The neighbourhoods are really small so you can imagine that every sim knows just about every other sim in the area. Now if you created that sim with a grumpy or angry personality then thats how he may react with others. I doubt it's a glitch as there are NCPs that have the same personality traits as your sim. If Its really bothering you, you can delete that sim! Or go into the lot he is at and change him to command only. (I can't remember where to change the option or whether it will even work! Id imagine it will be in settings somewhere.)

As we always say, you can't change anyone! You have to accept them as they are...well Im afraid your sim is no different!

Good Luck!