Spelling mistakes definitely annoy me. And yes, 'definitely' is a frequent culprit. Oh and I hate 'should of' and 'try and ... '
But what I just can't get my head round are very professional-looking, very expensive shop signs, with howlers ... If you're going to spend a lot of time and money making a big, professional sign, at least take a couple of seconds to check the spelling ...
My local high street must be the worst in Britian for that. I took photos of 12 examples and I'd only got about a quarter of a way up the street.
My two favourites are the 'Estate Agents - Commercial and Residencial' and the wonderful 'Bearue de Change'