I travel to Canada semi-regularly, & they always take a while paging through my passport - I have two fifty-page passports stuck together, with a LOT of visas in them, including some defunct Canadian study/work permits. My most recent trip was the fastest through immigration - I had a kitten with me, & that was all they seemed to notice.

I've never been searched going through Canadian immigration, but an over-officious, very young British Immigration officer did a thorough search last November & took my passport away for a week - seriously disrupting my work & personal travel plans. Interestingly, though they dug through all my dirty clothes, he didn't seem to notice the massive package of biltong (like jerky, but better) I was carrying for homesick southern african friends, & he didn't so much as look at my laptop, though he photocopied all the papers I had.

Three colleagues of mine were stopped & questioned by British Immigration on another occasion because one had recently been to Israel, one had been to Egypt & the third had a whole passport full of Saudi visas. Apparently they didn't look like real terrorists, tbough, because they were let go...