cant remove plug wires!

i have a 2000 kia sephia and I can't get the plug wires off - do they just pull straight up? I've broken one already using a pliers -

unfortunately, a lot of manufacturers are making plug wires "one time use" these days, meaning they're made so that they pull apart when you try to remove them, this way when you need new plugs, you'll also have to replace the wires