Being so comfortable with technology that I consider myself quite tech-savvy, it's a huge bummer when technology doesn't work the way it's supposed to.
You adopt a new online service and give it your support — but it crashes incessantly, making it impossible to appreciate their innovation. You adopt a new gadget early only to be the one to have to deal with the bugs. You make a service call for a broken or malfunctioning machine — and have to face off with someone who knows less than you patronizing you (don't even get me started on the gender thing).
No, there's not much worse than technology not working when you need it or how you need it. We all have our tech pet peeves. What's yours?