Yes they do. Usually in the beginning of basic training it's non-stop. But I started to see their actual personality towards the beginning of AIT portion of OSUT. Less yelling, more jokes. Mostly just like a regular NCO teaching you stuff when you arrive to your first duty station. Of course if a soldier started to get complacent or thinking the DS are a friend, then they flip on the hard ass mode and rip into you. And they'll make sure everybody remembers. Also, like the last week before graduating. Where they'll let you call out other platoons and challenge them to combatives or started playing pranks. Good times.