I would add that BMI (weight/height2) is just a neutral stat that helps specify body sizes, like weight or height themselves.
It may not be the magic "health number" some sites make it out to be, but it definitely helps to set boundaries for a more realistic weight ratio. If people abuse statistics to feed their fears and prejudices, that won't necessarily be a problem of the numbers.
"I weigh 100kg" already gives some information, but "I weigh 100kg, and have a BMI of 25" specifies it a bit more, it's just another way of saying "I weigh 100 kg, and am 2,00m tall".
"I weigh 200kg, but that's an average weight for a big guy like me, because I'm 2,00m tall" can be argued with the resulting BMI of [200/(2,00*2,00)] = 50 ! "Dude, your weight is at an extremely high level, it can cause serious health problems. By WHO standards, a person of your heights is obese at 200kg."
But if you panic for being 68kg at 1,65m because you're at a BMI of 25(!!!), then calm down - don't change your training, cut down the spaghetti for a few weeks and just keep a watch on your calories intake. You're probably not dying more than the rest of us, and you're not ruining your chances as a happy single for having a few chubby weeks. Aesthetically it might even work for you.