Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Why so different?

My sister ordered 10 50-Pack Spindle Memorex 4.7GB 8x DVD+R for me. 8 of them worked ok (about 1-2 coasters/pack). However, the last 2 packs were really bad (80/100 coasters). They either got waterdrop-shape or spring-shape on back when recording. When they were played, they would be silent. I couldn't figure out why the disks worked so different. I would never buy this Memorex 4.7GB 8x DVD+R again. Instead, I might change to Ritek, Verbatim.