...it randomly pulls/drags something you select for no reason!
...it refuses to select the HUGE obvious thing right in front of you!
...a dial magically turns slower if you're not looking directly at it!
...you render a closeup of the floor that was invisible in preview!
...smoothing polygons turns metal bars into funhouse balloons!
...you add a prop and it sneakily hides somewhere just for lulz!
...you position a rope/chain/etc then realise it bends the OTHER way!
...you turn a prop 90 degrees and suddenly it only turns on two axis!
...you load a prop and it then asks you to locate a nonexistent file!
...you tell it NOT to look for more missing files and it does anyway!