Why are exothermic reactions easier than endothermic? If we talk about  electric heating then we have simple elements in which we apply electrical energy which gets converted into the kinetic energy of the electrons which heats it up.
But while cooling, we need to take away energy from those electrons doing their dances, since we do not even have to apply energy and rather take it away it should have been easier but we know it is not.
Why is it easier to give free electrons kinetic energy than it is to take it away?
Similarly if we see on the reaction front exothermic reactions are much more easier to sustain and perform than endothermic ones, this also seems to show that endothermic reactions must somehow be difficult than exothermic ones in general.
Why does it seems so?
 A: It is easy to give something energy, but it is difficult to take it away, because you just can't "take away", you have to "make it give" you the energy. Normally you cool something by having something cooler that it can give it's energy to (Fridge :-P ). If you get really low, you can do Laser Cooling, which works because you make the particles give more energy back than you gave.
So, you can never "take away energy", only "give". For cooling, you need to "make the particle give".
A: I want to point out, that we tend to live and think on the (rather) low end of the temperature scale.
You would run into the same kind of problem if you're at very high temperatures and would like to continue raising the temperature. At that point I'm sure it'll be easier to "take" energy away and thus reduce temperature.
A: I believe the question should be broken in two parts: (1) how to convert energy from or into heat, and (2) how to bring/take away the heat to/from the object you want to heat/cool down.
The process (2) is actually symmetrical whether you want to heat or cool: phenomena such as conduction or radiation give the same heat flow with a reversed sign whether the temperature difference is positive or negative.
So the asymmetry lies really in the energy conversion (1): we have many exothermic reactions at hand, and mostly rely on combustion, while sustained endothermic reactions are more difficult to exploit in engineering conditions.
A: I would assume that entropy would be a large factor. In any conversion of energy from one form to another, there will naturally be some degree of waste heat (entropy) generated. Therefore, heating is like rolling something downhill- it's the "natural" tendency anyway. Cooling something generally involves moving heat up a gradient, which requires more energy because you're still generating waste heat.
In both circumstances, the overall entropy (assuming it's a closed system) must increase. In heating that works to your advantage, while in cooling you're fighting against it. As an example, if you take a refrigerator, thermally isolate it, and plug it in, eventually it'll overheat.
