The simplest explanation isn't the less complex in terms of the difficulty to understand it, but the simplest explanation is the one that has the less assumptions. Lets say that gravity may occur due to the complex laws of physics that try to explain it, or from a demon that is pulling us down. The idea of the demon may seem to be the simplest one, as it doesn't have many complex calculations, but in order to explain that theory we should explain were did the demon come from, how can we not see it, why is he pulling us down, and many other assumptions and questions that would be impossible to answer. The fact that the laws of physics carry the less assumptions makes them the simplest solutions to a problem.
Is the simplest explanation always the better one? Not necessarily but as the phrase goes "all other things being equal" then I'd say it's a good start. The key is all other things being equal. I honestly think this works best when it comes to things like conspiracy theories or motivations. Again, I totally get the opposite side but I consider this more as guidelines, not hard and fast.
Ockham's Razor may be good for science, but bad for philosophy and religion. That type of reductionism can be problematic; it excludes too much data. Not all data is scientific. If you say we should only believe what the scientific method can prove, you're contradicting yourself, for the principle itself cannot be proven by the scientific method.
The simplest explanation in the context of Ockam's razor is adding things you really have no reason to add to the explanation. It is about needlessly complicating the matter, or choosing answers that beg more questions than they answer.
Commonly used these days in talking about god claims, people look at the beginning of the universe. They leverage god as an explanation, when it simply complicates the question. If the universe needs a creator, why doesn't go need a creator? It is invention of an infinitely complicated thing to solve a problem we don't have the information to solve yet, with no particular reason to add that variable other than people wanting an answer.