I also use a Phillips Air Floss. Works great, but the motors die like clockwork ever 12-14 months. I bought the extended warranty and return it to the store. If you don't want me to keep returning them fix the bloody problem with the motors. It's not like I enjoy traipsing to Best Buy ever year when the damn thing breaks.
And don't get me started on cell phones. Use slightly cheaper ram and their performance goes to crap. Not a problem if you buy $700+ flagships. But I buy $250 mid range phones. I go through two or three before I find one that isn't crap and do that about every 2-3 years (mostly because radios improve and I want the better reception/new bands).
If you're savvy there are plenty of legit reasons to return lots of stuff. Companies will make barely functional crap if you let them. Returns are the one thing that lets us punish them. And again, I'm not scamming anyone. In fact, I'm pretty damn pissed companies are wasting my time with their God Damned corner cutting.