Riding on Flight 16 yesterday (Sun., Jan. 19), our 737-700 hit the Miami runway with terrific impact. The look on the face of the lead F/A said it all. I noticed the return (AS 17) was almost 3 hours late. Assume this may have been because of that. Clear day, long runway, not much wind. I'm new to the airline. Hope that was an isolated incident. Didn't inspire a lot of confidence. I know anybody can have a bad day, but you'd rather have those confined to less critical functions.