1. **State the problem:** Simplify the expression $6 + 2 - \left(-1\right) + \left(-8\right)$. 2. **Recall the rules:** Subtracting a negative number is the same as adding its positive counterpart. So, $-(-1) = +1$. 3. **Rewrite the expression:** $6 + 2 + 1 - 8$. 4. **Perform the addition and subtraction step-by-step:** $6 + 2 = 8$ $8 + 1 = 9$ $9 - 8 = 1$. 5. **Final answer:** The simplified value of the expression is $1$.