This isn't the same, really, but it drives me UP THE WALL when people can't spell 'definitely' correctly. Maybe I spent too long studying morphemes, but the proper spelling seems so obvious. But! What's even more annoying is that my brain plays a funny joke on me, and sometimes when I'm thinking thoughts in my head, I'll say, 'Oh, I should defiNATEly do that. That's deFIANTly the right choice.'

I think a sign of too long spent working at home is that you start teasing yourself.

Ta for the link, Em. I'll no doubt have great fun reading it and enhancing my pedantic powers (for good, of course).

One thing that makes English such a versatile (and confusing) language is how seemingly synonymous words convey distinct meanings – insure/ensure are a classic example. It's often the case that the words share a common origin, but at some point they were codified to have different meanings.

Despite what certain Guardian columnists may have written recently, language evolves but too much so-called evolution is actually laziness and ignorance in an unflattering disguise. Objection to such 'evolution' is only as natural as words changing their meaning and use – though I'll happily disabuse the business community of the idea that 'leverage' is an acceptable verb, especially when it has nothing to do with finance.

I am utterly ashamed to admit I always have to stop and think about principle and principal and never have a clue how many sets of double consonants (ents?) there are in unnecessary. Or, indeed, embarassed, which I am rapidly becoming.

I'm afraid I'm 'definately' guilty - that's how I pronounce it, with an 'ate' in the middle.
Passed and past I always have to think twice about.
And further and farther - is there a difference between the two? Farther always looks wrong to me (too close for comfort to father) but I see it used a lot on US websites.

"Farther" usually refers to physical distance. "Further" refers to an extension of time or degree. (When I'm writing, I just remind myself that "further" is not a literally travelled distance, and that always helps me.)

A recent edit contained some confusion of genteel and gentile. I was mildly amused, then mildly worried that I find such things amusing.

Among millions of other semi-dyslexic errors in my writing and spelling, I always mix up minor and miner, but at least it's funny.

One that annoys me is people using loose instead of lose. It never ceases to amaze me how many extremely well edcuated people get this one wrong.

I wrote 'alright' in a short story recently and was criticised (or criticized) by a reviewer for not using 'allright'. 'Alright' is, according to her, horrible.
All these versions are in my dictionary (I've just checked) so I don't see the problem.
At least I didn't write 'alwite' which seems to be the accepted pronunciation these days.