The Hardest Part of performing is making it look natural

I've always loved Blondie's music, but I also always thought Debbie Harry seemed incredibly uncomfortable and devoid of stage presence, at least in the band's music videos.  Example:

Great album and song, painful performance

Seriously, it reminds me of Britney Spears' infamous and disastrous MTV Awards appearance:

I never saw Blondie in concert.  Was Debbie as awkward in live shows as she was on video?