For the first time ever, I got picked for secondary on Thursday going through DEN. I had to make a last minute change to my flight, heading to YOW instead of YUL, which is probably what triggered it. My first thought when the woman at security called over the agent for secondary was "oh SH!T", but it really wasn't a big deal. Both agents I dealt with were friendly, well-mannered, and didn't paw through my things unnecessarily.
All that really happened was I got to skip ahead and go through the puffer instead of the regular line, they swabbed both my laptops, my cellphone, and the inside of my bag for explosives, and after he noticed my macbook pro, we chatted about the new iPhone coming out in June. I'd go to secondary any day if that's all it is and I get to bypass everyone else in line.
Though I'm sure not everyone's experiences are as positive as mine was.