“My Sharona” is a totally cool and motivating riff (if you don’t feel like practicing at all for example).
The difficulty with this riff lies in the large gaps between the two notes. To be exact, it is an octave, which is good and close on the guitar, but one string has to be left out.
So you can see this riff as a riff exercise on the one hand, but also as an octave etude on the other! : P