modelsim problem regarding input initialization

Hello,

i recently encountered a problem when simulating in modelsim which was with the outputs not resposnding to the inputs. Then once i initialized all the inputs the outputs responded normally.
since i implemented an active low reset, and set it high at the start of the simulation, nothing worked then i set it for 10ns low and high after that and it worked.

any particular reason for this ? is it good practice to initialize all inputs before starting the simulation ?