Another typo that makes me crazy is when someone uses an apostrophe for the plural form of whatever they are describing. For example:
"All Corvette's have V8's" or "not all VW's are built in Germany"
In English, the apostrophe shows ownership or replaces the letter "i"
Since Corvettes, V8s and a VWs can't own anything, the apostrophe must be interpreted as if to replace the letter "i".
Therefore, were the apostrophes to be removed, the first sentence would read:
"All Corvette is have V8 is"
and the second:
"not all VW is are built in Germany"