Does it? It sounds to me like it implies that you wouldn’t clap your hands unless you are happy, you know it, and you also want to show it. All three must be true for it to be hand-clapping time.
What difference would you expect if the “and you know it” clause were omitted?
Suppose there are indeed some people who would clap if the clause were omitted, but refrain when it’s included. The implication would be that these people are happy and don’t know it—and yet they clap anyway.
If they didn’t clap, adding the clause would have no effect and its inclusion would have no motivation.
Does it? It sounds to me like it implies that you wouldn’t clap your hands unless you are happy, you know it, and you also want to show it. All three must be true for it to be hand-clapping time.
What difference would you expect if the “and you know it” clause were omitted?
Suppose there are indeed some people who would clap if the clause were omitted, but refrain when it’s included. The implication would be that these people are happy and don’t know it—and yet they clap anyway.
If they didn’t clap, adding the clause would have no effect and its inclusion would have no motivation.