I bought a Merida Speeder 10 to commute to work with (all concrete bike paths and asphalt).

The first week I bought it the rear wheel had become bent and was scraping against the brakes. I returned the bike to the shop I bought it and they re-trued the wheel.

A few days later the gears started skipping. After 2 days it got so bad I couldn't use low gears and I again, returned it to the shop. They replaced it with a brand new version of the same bike.

A few more days after that the same thing happened - the chain started jumping off the sprocket when using low range gears. And, again, the problem got worse with every ride.

I've never had a brand new bike that was twice unusable in just 3 weeks.