Every time I have traveled from YVR back to the US, I have been subjected to secondary screening by US Customs, most likely because I only had carry-on luggage and I was traveling solo. They always seem very suspicious of me and ask me lots of questions to try to make me inadvertently "confess" to some awful crime. Once I was asked, "did you use any illegal narcotics while you were in Canada?" I would love to know how many US citizens visit Canada for the sole purpose of engaging in illegal activities.

Having said all that, I find Canadian immigration and customs to be equally annoying and suspcious of me. I've been subjected to lengthy interrogation and a thorough search of my carry-on luggage almost every time I have visited Canada. I guess they don't like solo travelers either!