Unless you have been a victim of writing the wrong word of a Seed down or the incorrect order of it, you do not know how frustrating and desperate such a mistake can make you feel.

When creating a new Seed, always double check its validity.  Not only by writing it down and double checking it with your own eyes.  To me, even if the Wallet checks two or three words, it means nothing.  There could always be an error and I try to minimize it.

The way I do it is as soon as I write down the Seed, I close the Wallet, then re launch it and use the Restore option.  Enter the Seed from the paper I just wrote and go from there.

I wrote words in the wrong order before and at first glance it looked right.  Next time I had to restore my Seed from my paper, it said it was wrong.  I got desperate for days, until I tried to swap the word with the previous and luckily it did work for me.

Check your Seed twice.  Do not be lazy.