Flying a plane when you can't see out the window feels remarkably different than flying visually. When you're in a cloud you never quite know if you're about to fly into a mountain. All the instrument training is to make sure you avoid the places where the mountains are, but the psychology of not being able to see the mountain you know is nearby is significant.
One key piece of how we stay safe in IMC is air traffic control radar. ATC generally knows where your plane is and helps keep you off the rocks. Often in NorCal the controller gives you vectors, tells you to fly a specific heading for a few minutes while they route you somewhere convenient. Once you're on vectors you are 95% trusting the controller; you're off the charted path.
I've been very impressed with the quality of ATC, particularly here in NorCal. But controllers are human and make mistakes, sometimes mistakes that get pilots killed. There's a training crisis in ATC right now, the controllers hired after Reagan busted the union are reaching mandatory retirement and they can't train replacements fast enough. The rate of mistakes is going up. Flying is still very safe but it's in the pilots' interest to look out for themselves.
The best defense for a pilot is always knowing where you are. Situational awareness is remarkably challenging with traditional radio navigation, where all you may know is you're somewhere north of a beacon 30 miles away. I'm at the stage where I still regularly get confused: am I west of the airport or east of it? Fortunately my airplane has GPS, a map with a terrain database that shows my position at all times. If I'm being vectored into a mountain, I'll get ample warning. But the FAA still treats GPS as an add-on in instrument flight, an extra, it's not necessary equipment. So we learn how to fly without GPS too. I wonder if I'll ever be truly comfortable flying without my electronic map.