Particularly If you have a crush on one of those men
It depends on the situation. Is he married or in a relationship? Back off. Is he single? Best consider office policies before even initiating anything with him. However, if something does occur between you and a (single) co-worker, consider the possibility that the relationship doesn't work out ...how will you cope with being around him afterwards?
If you have a crush on one of them, then look for signs to see if he feels the same. If he has a wife or a girlfriend then leave him alone. Always maintain a professional attitude at all times. You don't want to make other people uncomfortable around you.
I am in that situation. Just whatever you do, DO NOT get into a relationship with one of the guys. Because, if it goes south, you are forced to see him every day! Just sayin.
what if the person is shy and there are no written office poilicies about this?
Depends on office policy and the person's relationship status.
Then the rest is up to your imagination