I find your grammar correcting a little over the top sometimes (coming from the son of an English professor, so I get more than agitated about bad grammar in real life), but holy MOLY if I see Computer use "then" for "than" again... Haha
My grammar fascism (I refuse to adopt the "Nazi" label) is largely a result of the fact that I tend to read and write more than I speak (which has its own deleterious social effects), even though my speaking is half-slang as it is.
When I type things with my phone I just quickly type what I want .
In other words, you don't use proper syntax because you don't feel like it.