Open your novel file. Do searches for “that” “and “then” and “large” and “small”and “very” and “ly.” See how many of the hits you can live without.
“This was the house that she had always wanted. She worried that Bob wouldn’t like it.” Nothing wrong with that, is there?
Not really, but consider this:
“This was the house she had always wanted. She worried Bob wouldn’t like it.”
Feel any loss from dumping “that?” Didn’t think so. It seems like a small deal, but over the course of the manuscript these little bits of unnecessary padding start to act like those little blood cells in the TV commercials that build up until they form a clot that stops your heart—or in this case kills your book.