Distribution of Expectation function into a $|X-Y|$

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We know that $E(X+Y) = E(X) + E(Y)$. But why is $E|X-Y|$ $\ne$ $E|X| - E|Y|?$

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If $X \ge Y$, then

$$E|X-Y| = EX - EY$$

Otherwise

$$E|X-Y| = EY - EX$$

Neither of which are necessarily equal to $$E|X| - E|Y|$$