"Frustration" can be one of the most fun things in SHIII.
Today I was on patrol in the Baltic under GWX 1.3. It is late afternoon when I sight a small Polish merchant. I'm on a Type II, so I have only five torpedoes. I decide to fire the first one: nothing. It was either a dud or a miss.
I close the range and fire a second torpedo at 800m. Still nothing. At this point I was out of position, so I surface, the merchant sees me, and the chase begins. After a LONG struggle I manage to finally hit her with the third torpedo. The ship slows down but she doesn't sink.
So I was down to two torpedoes, one small merchant damaged and nothing else. To add insult to the injury, I had forgotten to properly man the forward torpedo room, and no one was reloading the weapons. So I send men to the room, I wait for one more torpedo to be reloaded, I manouver AGAIN so to get in firing position...
...And a flight of four Stukas comes out from nowhere and flattens the merchant. BOOOOOOM!!
Well, it was fun, but I can imagine the U-Boat skipper's language in real life...