Differences between German and American submarine life and combat

[U-96]

German U-Boats and their American counterparts had similiar technology which was common in world war two before the entering of the type XXI Electroboot.

But also I would imagine their tactics, philosophies, etc were different. Germany's U-Boats formed the bulk of their navy, However only a small percentage of the U.S. navy were Diesel Submarines. (I tend to call any diesel sub U-Boats but most don't so this terminology is to avoid confusion)

So the question being, What did they do differently? The only one that comes to mind is that I've noticed that American subs tend to keep their distance while German U-Boats would try and get in close.

Also Americans seemed stricter on their dress code while on U-Boats the crew wore mostly their home clothes. I've never seen photos of returning American crews with beards.

I find U-Boats more facinating in both the technology and the lifestyle however I'd be interested in knowing how it was for Americans as well.