not to mention, throwing a nade right at their feet can still be greatly effective while you are having a shootout. They will have to decide to either waste time throwing it back while getting shot at, or jump into cover. Either way it makes an excellent distraction to surpress enemies.
Agreed, I've found it better to see where the enemy is running and throw it ahead of them. As I said before, the trick is to use grenades as aid to your combat, not a primary weapon.