you absolutely should not look at a TV's picture quality in a store to come to any type of conclusion. that's patently the worst thing to do.
in short, they know what they're doing. they will either crank up all the settings to look bright and shiny in their well lit environs, or worse yet they've been known to fine tune the pic quality of the TVs they either intend to or need to move in short order.
you are much, much better off going online and finding a well-established vid/audiophile user community/forum and read the reviews and experiences of people there. they'll even go as far as include their fine-tuning recommendations based on lighting/room-size, etc...
in other words, take the time to educate yourself, and you will easily avoid being burned.
