Instruct: Classify Amazon reviews into positive or negative sentiment
Query: THE WAVE NOT FOR POOR BALANCE OR PEOPLE WITH BACK PROBLEMS

I brought this and its really hard to stay on it, Its real slippery, you have to make sure you have rubber on the bottom of your shoes. If you have back problems or balance problems this is not for you. Infact its scary. They should have made the top and bottom with more rubber on it. Its so slippery. I plan on taking mine back to the store. An accident is about ready to happen. i HAD TO TRY 3 DIFFERENT SHOES AND ITS STILL BAD. THEY NEED A NON SLIP ON THIS ON THE TOP AND ON THE WAVE PART WHEN ITS UPSIDE DOWN. I SEE THE POTENTIAL BUT I HAVE TIRED EVERYTHING TO STAY ON IT. ITS SO SLIPPERY EVEN WITH MY GOOD SHOES. I AM GOING TO HAVE HUSBAND PUT THE NON-SLIP PAINT ON STUFF ON THE WAVE PART SO I CAN STAY ON IT. YOU CAN HURT YOURSELF BE CAREFUL.