* I have to turn off gatekeeper to run unsigned apps.
* I can't write into /bin or /usr on my own machine without flipping some magic option
* I can't run gdb without some complicated signing dance I have to do every time I update it.
* I can't run dtrace without rebooting and switching some secret flag off. I have to tell other people to turn they same thing off so they can dtrace applications.
That's just straight off the top of my head. The dtrace and gdb things are particularly annoying, as it makes life harder for me to get other users to do simple debugging tasks, and there is no simple workaround, just complicated instructions.