Too many people pick up or purchase a rod and line it up, then may not be happy with the rod for various reasons. 

1.  They should try the rod with different styles/brands of lines and also be willing to accept using a different weight of line on the rod to make it feel "right."  Some people get stuck on the "number" inscribed on the rod and refuse to try a different sized line “because the rod says………………” .  This is a big mistake !  I have fine tuned many rods for myself and others if they are willing to accept a different line size.

2.  Or............. people buy the rod for the way it feels when they "air test" it in a store, and then it does not feel the same when loaded with the line they chose.

3.  Thirdly, too many people "lawn cast" a rod with a good line,  but then in a real fishing situation, the rod does not really perform for them as it did when casting over grass.   I am somewhat guilty of this myself.  Many rods feel great over grass, but a rod and line really needs water to exert the pull a rod needs to set up a backcast.   My biggest problem is when I take the rod to the stream and tie on not only a fly, but TWO flies.  The battle then starts between the cast flies and the rod does not feel the same as it did when casting with a bare leader.  Aside from changing my timing, UPlining the rod helps many times to make the rod bend deeper and "kick" the flies to the chosen spot.  Many bamboo rods I have cast without a fly (flies) on it felt great, then when I got the rod to the actual river,  I had to "push" the rod too hard to get it to lay the flies out as I wanted, especially tight spots.   I am a somewhat aggressive caster,  but I also want the rod to bend and deliver.  I do not want all the action to come from my arm alone.

If a new rod cannot actually be used in a live fishing situation and you are stuck simply waggling it in a fly shop, be willing to make some line adjustments later to make the rod really sing for you.