YVR to LAX transit

Photo taken on Jan 11 (we lost Jan 12 on our travel due to International Date line). 
We are on our journey home. Westjet from YVR to LAX for a 4 hour long transit.
Immigration and Customs to entering the USA is an experience.
= RAMDOM check by TSA, issued border pass in CANADA before boarding the flight (interesting but worked). The number of check and recheck and recheck of your boarding pass that got me puzzled in a matter of meters apart.. LAX is a huge airport and signs directions is not their forte.