With all the negatives, why would anyone want to be on a submarine in WW2?

Certainly, life on a diesel submarine can be primitive. The boats did stink, they were cramped, they didn’t ride well in heavy seas and you may not have been able to get a full shower during the entire patrol. You may not have seen the sky for weeks at a time. Even if you were a lookout, you still may not have seen the sun for weeks since the boats were often submerged during daylight while in the patrol area. Diesel boats can be pretty unpleasant.

Still, sub sailors did think it was good duty. There were many advantages in being aboard a submarine. Those advantages are different in peacetime than they were in WW2, but there were and still are many reasons to volunteer.

During WW2, the main advantages appear to have been:

1. Because of the Great Depression, a significant attraction was probably the extra submarine pay. That appears to be about 50% added to the base pay for sub sailors, at least for the junior ranks. This was very important to sailors when their families were still struggling financially. This extra pay would often be sent home and could be very helpful to their families.
2. Submarines were the only ships that could take the fight back to the Japanese early in the war. Even as the war progressed, it would take a while for the rest of the Navy to take the fight to Japanese waters. There was a real desire to avenge the attack on Pearl Harbor, and service on submarines was the quickest way to start getting even. Although there were the occasional attacks on the Japanese islands, such as the Doolittle/Halsey air raid on Tokyo, submarines were providing a more sustained fight.
3. This may seem a bit morbid, but some men thought that the worst thing that could happen to them would be to come home maimed. Submariners were less likely to be maimed, to lose an arm or a leg. The odds were greater that they wouldn’t come home at all, but they weren’t likely to come home maimed. For some sailors, that was preferable.

Some advantages still applied after the war:

1. The crews were better. There were normally more volunteers for submarines than there were billets (positions) available. Naturally, the submarine service took the best available. Currently, reports are that you have to be in the top 15 to 20% of the Navy to be considered for submarines. That is true even for non-nuclear positions such as storekeepers, yeomen (admin) and cooks.
2. Submariners were – and are – an elite group. It was a chance to be part of something special.
3. The work was more interesting. They often operated independently and without much direction from above or afar. Sailors on submarines couldn’t talk about much about where they or what they did. Even the old boats could be doing interesting work such as training with divers or just practicing intelligence gathering and photo reconnaissance.
4. You could learn something new nearly every day. Sailing a submarine in three dimensions was, and is, more complex, challenging and interesting.
5. Submarines were generally less formal than surface ships.
6. Submarine duty could be a faster route for promotions. For officers, it could be a faster route to commanding your own ship. (This was no true longer after the war particularly with the advent of nuclear power in. the 1950s.)