Here we go again with Minecraft 1.8 being glitchy and rushed. I love the new slime blocks, but they screw up the pistons. Whenever I try putting a slime block on a piston then putting a redstone block on that slime block, Any piston placed in a 3x3 radius extends, even if the redstone block is diagonal from the piston. Also, too many slime blocks, randomly, causes the pistons to create more slime blocks if you push too many of them, but if you go near those new slime blocks they dissapear. But it isn't just the slime blocks that f*ck up the pistons. If you dig a 2 blocks deep 1x1 hole, put redstone there. then put a wooden pressure plate above it. right next to the redstone dust should be a sticky piston to push a block upwards, and then put a block for that piston to push. The end. Shoot the pressure plate with an arrow, then pick up the arrow.
Did the piston pull the block back down? No. It didn't. You have to break the block to get the piston to turn off. Complicated, isn't it? This is what I call a load of bullsh*t. Test this for yourself!