It seems like the sentence still makes sense without the word "necessary." If I say "you're less motivated to do the actual hard work" instead of "you're less motivated to do the actual hard work necessary", what gets different?
Native speaker’s answer
Rebecca
You are correct. The sentence does make sense without the word "necessary." Both sentences have the same meaning. Having "necessary" makes the sentence a little more formal. Since this gentleman is giving a speech to a larger crowd, he may have wanted to sound more formal. Regardless, you would be fine using this sentence with or without "necessary."