What do you mean, pick [] for qw? That you've seen people pick different delimiters for different quotelike operators and stick with them? I've not seen this happen. But the whole point of freedom in delimiters is that you choose something that makes sense for whatever you're quoting in that instance. Just like s/// is silly on pathnames (because of "leaning toothpick syndrome"), qw() is a bad choice if one of the things you're quoting is ")-:".