Velma --- she's the fun one. I always found Roxy a bit annoying and unappealing. Plus Velma sings and performs in all the fun songs --- All that Jazz, for example.
When someone blunders, we say that he makes a misstep. Is it then not clear that all the ills of mankind, all the tragic misfortunes that fill our history books, all the political blunders, all the failures of the great leaders have arisen merely from a lack of skill in dancing. - Moliere