Ladyazh,
Do you watch Monk on the USA network? He plays a character with obvious OCD. That might help with explaining it.
OCD and taking food from someone else's plate could be something like they can only take food from the person to their right, or from a woman, or from the person to their right only if they are a woman and their name begins with an L.
As Anotherhiggins pointed out OCD may have no concieveble bearing on reality, or it might be an over-reaction to everyday things. Something like having to wash your hands after you touch a doorknob beause you read that 70% of the baterica and viruses you pick up are from doorknobs/doorhandles.
***************************************
Have a problem with my spelling or grammar? Please refer all complaints to my English teacher:
Ralphy "Me fail English? That's unpossible." Wiggum