The freedom of experimentation is crucial

If a software engineer has to struggle against lots of tedious work incorporating every single change then very often he simply abandons it and doesn’t change anything. In other words he would rather leave some poor solution that more or less works then replace it with something really valuable. His creativity is simply limited by the amount of additional effort that every change requires. Above problems can be caused by lack of proper tools, messy and unmaintainable code or even so trivial thing as slow workstation. There are people that don’t perceive it as a real problem but in my humble opinion they are wrong :).