A few of the things that I think a lot of tea drinkers look for, at least with Chinese oolongs and puers:
* aftertaste (strong, lingering)
* texture (mouthfeel, "thickness")
* complexity (the taste isn't too one-note, and changes over multiple infusions)
* clarity (in the brewed tea broth)
* quality of the leaves themselves, and presence of a good "tea base" (goes kind of with texture above)
* durability (how many times the tea can be brewed)
And of course, some people have higher or lower tolerances for bitter or astringent tastes in tea, so these characteristics may influence their choices.
Again, I am very much not trying to say that lower priced teas are not good or that you can't find some great ones, but overall, I think you will tend to find more of the qualities above in an expensive tea.
So I wonder is that what a lot of tea drinkers think if the tea is a higher price it must better?
Again, I am sure there is an element of that... but it is also true that it's rare to find a really exceptional tea for a too-good-to-be-true price. Also, I certainly don't think it's true that everyone likes a tea once they know it's expensive - I've seen plenty of people not like teas that they knew were quite expensive.
Now everyone has a different idea of what's "expensive", but I think you will find that most people here can't afford to drink the most expensive teas every day. Most people have some fairly inexpensive teas for daily drinking.