Dutch ovens? Elaborate. I'll assume you're making a strange reference to an urban dictionary phrase (read as: not a), since that's what google turned up. In that case, it inflicts intended suffering on the target and gives you gratification. Any malevolent action does this, really, so kind of silly to mention it.
Thorns on roses? They protect roses from animals, of course.
Crystal meth? Gives someone an enjoyable high, and makes a lot of people a lot of money.

Hatred is the only thing I can think of that is truly useless.

Depens on your criteria of useless. If something doesn't do what it is supposed to you could say it's useless. But then again, it may be somehow re-entered into the cycle of life to create something else (i.e. decomposed or something).

Maybe this thread is useless, by thinking about useless things you don't really accomplish anything. Owell, that's my part to the discussion.

I tell you something that's useless. err Nothing. You're right, everything has benefit to something.

Nothing is useless. If they made it for a reason, no matter how stupid it is, it is not useless.

Ex. There is something called the Tiddy Bear where ladies put the bear on there tits while there driving. The bear is supposed to release a tiny bit of pressure for the tit. Its stupid but it might benifit Rick Ross.

So basically nothing is useless.

I believe that everything has a purpose and a meaning. I feel like everything that happens in life is a trial preparing us for what ever lies ahead of us. I am a Christian, so I would obviously believe that eternal life is waiting for me... But everyone has different opinions, and it is really up to them to decide what is correct or incorrect, or in this case useful or useless...
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a good saying for those who think everything is purposeful or meaningful to someone:

One man's trash is another man's treasure

What about planets. For example, pluto, asteroids, mercury. Do those things have a purpose or you were refering to things on earth?

closed because I for one am sick of every thread turning into a christian bashing thread.