Oh yes, we were building and programming Lego Mindstorm robots in university. Also with the goal to go through a simple maze and follow a line. Booring simple everyone thought. But the thirst thing we learned, was to not trust our sensors. My expectation was, if the ultrasonic sensor said, there is 1 m to an obstacle, then there is 1 m of free space. Well, not really. Partly because the sensors were really bad and only worked reliable when the obstacle was in a 90 degree angle, partly it is in the nature of sensors to not be perfect.

I am still excited for robots though, but haven't worked on one in quite a while.