If you're not a part of what they're profiling travelers for - the obvious stuff like drug smuggling, bringing copious amounts of money into or out of the country, or other contraband, you shouldn't have anything to worry about.

Anecdotal evidence is my last trip to go snowboarding in Banff in Alberta Canada. My parents came along because they'd never been to Banff and were excited about seeing the Canadian Rockies. In any case, we land in Alberta and are going through customs. Scary looking dude looks at our passports and asks what we're there for. I say, "snowboarding" my mom says, "site seeing" we immediately shoot each other a look like, "Oh shit, that wasn't good.". Without a blink, border guy told us to move on and keep the line moving.

We both spoke about it and agreed that whatever they were looking for, we clearly did not fit the profile they were screening for.