The Brother P-touch label maker I now have uses tape that's got the lengthwise slit on the back now, too. Makes them much easier to apply - peel half and get it positioned, then peel the other part. At my previous job we had one of the earlier p-touch printers with the non slit backing and they were definitely a bear to peel.
Difficult to remove or not, they're still a thousand times easier than the old Dymo labels made on the embosser. Spin the dial, squeeze the handle, and without fail the next letter needed would be on the opposite side. Thkthkthkthkthk-click Thkthkthkthkthkthkthkthk-click Thkthkthkthkthkthk-click and then near the end you'd screw up and land on the wrong letter and need to start again.
that and the natural curl of the tape made them want to pop off if not thoroughly stuck down to an immaculately clean surface.
-Pat