In putting on a contra dance, it's standard for the caller to pick the dances and the band to pick the tunes. Since it's much more satisfying when the tune fits the dance, the band and caller confer briefly between each dance. For example, the caller might say they want something "smooth and pretty" or "energetic with a chunky A-part".
Sometimes, however, callers fall into a trap of referencing a specific tune: "Trip to Moscow, or something with a similar feel". They remember the dance feeling especially good with that tune on some prior occasion with another set of musicians, and they're hoping to recreate that pairing. The problem is, while tunes do have inherent qualities that affect how well they fit dances, there's also a huge amount in how they're played. Consider a caller who really liked the trancey interplay of the Free Raisins playing Ian Ball's Trip to Moscow:
And then imagine they ask Kingfisher for it and get something more EDM inspired:
Or Last Exit and get a full up almost polka-feel:
While the dance won't fall apart if they're hoping for one of these and get a different one, it's probably also not going to be a great fit for this spot in the program.
So:
Callers: instead of giving a tune as an example, try thinking of what you liked about it and ask for that.
Bands: If a caller names a tune don't just go and play it; ask them what they like about it in this context.