Why do they even have lines? For one, registration is a service that they have to provide to EVERY person attending. Namely, a seemingly infinite population of people to only 30 registers, but look at it another way. How long are you WILLING to wait? Probably around 1.5 to 2 hours. I kept my eyes on the time, and we got through in around 45 minutes or about 43% of how long I am willing to wait. Knowing how much longer I would wait, I am guessing that this was the reason the At-Con Registration and Pre-Registration lines were one-and-the-same this year, in order to accommodate the excess of staff found in 2015. This year exceeded the maximum capacity legal in the convention center (likely due to fire safety standards), so to mitigate how quickly people enter, the bag checks doubled their purpose of security and population control.
An army marches on its stomach and so do con goers. How much do you usually eat? Assuming that you watch anime because you were, after all, at an anime convention, I can expect that at least an hour of your time is spent seated in front of a computer or TV per day. And during the 4 days of Anime Expo, they are replaced with walking - meaning more calories your body was not expecting. So even if you did bring your own food for the con, you likely found it unsatisfactory. So, did you have to wait in line at the food truck? No, but you were probably underestimating how much you would have to eat.
Traffic is a science in itself. Obviously, if there is someone in front of you, your speed is equal to or less than that person’s speed. Raise that to the power of the number of people in front of you, and you now see why it's slow. This is probably why the aisles were wider this year. Since you take up about 2 square feet of space, the aisles were made at minimum 8 feet wide (yes, I measured it). Sadly, browsing people stop and take up to 2.6 feet or 33% of the movement space of the aisles, creating random bottlenecks. Hence, that is why you waste 33% of your travel time.