A processor wants to be fed a very stable supply voltage. The supply voltage must not jump up and down with the varying load you get from digital electronics. This means that the supply must have a very low impedance, so you can't have a series resistor between the power supply and the Vcc pin. On the contrary, you want wide enough PCB traces, and you want capacitors between Vcc and GND.

The processor will not burn up if you:
- supply the correct voltages and with reasonably fast rise/fall times.
- run it within the allowed ambient temperature
- keep the voltages on all I/O pins within allowed limits (static voltages and ESD discharges)
- have reasonably fast rise/fall times for digital input pins.
- have current limitation on output pins
- don't try to overclock it
- observe the total power loss from all output pins, i.e. will all output bins active, you may need to limit the total current, even if each individual pin is within the allowed current.

I may possibly have forgotten an item or two, but the gist of it is that processors don't die if you are careful and follow information from the datasheet.