How important is it to have identical speaker cable length?


I have a situation where my speakers are different distances from my amp. Would it be wrong to pair a 3-meter cable to one speaker and a 2-meter cable to the other or is it really just a theoretical issue? Many thanks in advance for your thoughts!

benchwarmer
Not an issue at all. Don’t even think about it one more second.  One could be 8 foot and the other 20 feet and still no issue.  
Cables should always the same length however 1 meter difference should be ok.
You'll have no audible/sonic issues but you will most likely take a hit when you try and sell them afterwards. 
Electricity travels at the speed of light. Cables runs can be different lengths but I have always run the same length on both sides...just because.