THK Linear Bearing/Slide

I have bought a couple of THK linear slide units and both are like new. Are
they supossed to slide very easily? These aren't rough, just not easy to
slide. they are clean and greased. I have bought many thomson linear
bearings with the rods and they are smooth and easy but don't seem to be
tight. Have a little play in them. It seems you would rather a smooth
bearing than something that is hard to slide?? Is that the way most of
these THK bearings should be?

Thanks,

Barclay