It's not related to Smart Previews. Some more information (OS, LR version 5.?) and some screen grabs might be useful.
Sounds more like a preset added by default?
When the appearance of the photo changes a few seconds after it is imported, this is a normal feature of Lightroom. First you see the JPG preview in the RAW file, and then after a few seconds, Lightroom renders the unedited RAW photo, which will look different (and usually less pleasant appearing) than the JPG preview. Then, you need to edit the photo.
You can set up develop presets to be applied at import to make the initial rendered appearance of the RAW more to your liking.
Something else must be going on because smart previews and how your images look are totally unrelated. One of the limitations you will find with smart previews is that you won't be able to move from Lightroom to Photoshop. The smart previews are designed to be used when the master images are not connected to the computer you are using. Lightroom will allow you to make adjustments using its tools, but external editors will not be available. You need to determine what it was that caused the problem with your import.