There's a vocal contingent of internet users who like to claim that Summer Glau isn't much of an actress, mainly based on her appearance in Firefly, which isn't really a fair metric to measure her skills by. She's mostly mute for the entirety of the show's short run, only breaking out of her almost-comatose state when Serenity kicks into gear. For the TV series, she mostly just sits or stands still, keeps her mouth shut, and looks a little moody. When she does speak, it's important. In which case you could probably make a case for her being a bit naff, because when it came for her to finally have some proper dialogue in the season finale Objects In Space she kept flubbing her lines. Don't worry about giving her a hard time, online, retroactively though. Her lovely co-stars had that covered. Thanks to the spectacular out-takes that scene provided every other member of the Firefly and Serenity cast decided to make a running joke of it, using Glau's first name as a curse word whenever they forgot their lines or otherwise messed up a take. It's good to have that sort of support when you're appearing in one of your earliest roles. Adam Baldwin always was a jerk, eh.
Tom Baker is the Comics Editor at WhatCulture! He's heard all the Doctor Who jokes, but not many about Randall and Hopkirk. He also blogs at http://communibearsilostate.wordpress.com/
