I previously wrote that you can't have a pot pie without top and bottom crust.
And I really do believe that the best pot pies have both crusts. However, I also understand that sometimes, we are pressed for time and can't make our own pastry to line our pies. The best option in these cases is usually frozen puff pastry. You just thaw it, roll it out over your pie filling, brush it with an egg wash, and put it in the oven. No fuss whatsoever. The down side? No bottom crust, as the puff pastry will be soggy and doughy.
So, sometimes we have to give a little to take a little. Compromise that crust we love so much for the conveniences of frozen pastry. And while I still believe that both crusts are best, I am okay with the compromise once in a while.