I used to stick with lots of pressing and i was using really heavy for them.
But my delts were staying small.
But, since changing it to laterals(very light and super strict and 20reps) a lot, my delts has started to grow and my side and front delts are no more my weak bodyparts now.
They are small muscle groups. So its impossible to handle such a heavy weight like some do. OK, if you have very good genetic, they grow in every way.