Canada/Customs

I left my home at 5am, arriving at Atlanta Hartsfield International at 5:30 for a 7:55 flight to LGA. There I had a connection for a direct flight to Halifax, Canada. My first flight was great, on time departure, comfortable seating...I fell asleep before take off. On the otherhand, my connecting flight,well.. it was from NY so what could be expected other than delays delays delays. It baffles me that New York only has one runway for landing and taking off. I was forced to sit and wait for over an hour on the plane with no air-condition and the smell of wet human. (We all know that smell, don't we?) I can't stand it. If it rains and that causes you to smell sour then something is wrong my friend!
Eventually we taxied to the runway and took off. After landing in Canada I went through customs, who then sent me to immigration where I was questioned and scrutinized for over 2 hours! (where they do that at???!!!)

What part of tourism/ student did they not understand?