Why big diamonds and useless MacGuffins are a terrible investment idea

Suppose that you just won a considerably large ammount of money. Maybe it was the lottery, maybe a relative died, maybe you found a suitcase full of money (just make sure to remove the handcuffs and the severed hand).
So, the next obvious question would be: "How do i evade taxes?". But, i am yet to write something about that, so we will, unfortunately, have to move on to the next question: "On what should i spend the money?". Many people would first consider something like "mom's surgery" or "electrical bills" or "my son's college". But, for the more exccentric people, the dreamers, the weirdoes that don't know what the hell are they doing here, they might consider buying large, expensive jewelry, such as large diamonds or golden crowns or Lord knows what.
Well, this text is meant for those people. Think twice before you go to your nearest black market salesman!

A reocurrent issue with such items is that there will always be a Doom McEvil or a Thief O'Crime around desperately trying to fill the void their parents left with materialism. It's almost certain that your precious Pink Panther will be stolen, your Royal Crown will vanish misteriously, or your dog will swallow the rubber pig with the diamond (and Oasis will make a banger of a song about it).
While there might be a Hero McGood that retrieves the diamond succesfully, you'll still spend thousands, if not millions, on security, museum expositions, useless henchmen that will get their asses kicked, investigators, lawyers to hide the dead African kids that died in the mines to get the jewelry, and taxes (until i write the other guide). At some point, you will spend more money than the cost of the precious diamond, and i'm no economist, but that is quite the problem.
Unless, of course, the thingy is more valuable than money. You know, maybe it's the friends we made along the way, maybe it has a sentimental value to you, or maybe it's the key to find a cure for that werewolf curse you got a year ago. You were just minding your business when that damn furball popped out of nowhere in that park, and tried to kill you. At least he was polite enough to hand you over a pamphlet when he got back to his old self. Maybe he wanted to avoid getting a lawsuit. It's not like if you can call your lawyer anyways. What are you going to tell him? "Mr. Jenkins? Yes, it's me, i'd like to lawsuit Lupin Night, for passing me the curse. Yes, i know you are busy with the Africa child labor thing, but this is severely more important!".
Or maybe, you are going to buy something that will be much, much more valuable in the future. Properties, stock, an old oil rig that still has plenty of juice left. After all, when the Antichrist comes, he's gonna need plenty of fuel for the Christian-hunting machines, that is, until we find a way to use their blood as fuel.
In conclusion, don't buy the MacGuffin, unless it's more valuable than it's own price.

And with this, i bid farewell. Dr Cunningham is calling me, and he said that if i behave well this week, i'll get chocolate pudding every lunch! Man, being on a psychiatric institution rules!