I'm pretty verbose, I love my words, and people around me sometimes come to me with questions about words or their history and the like... and I still make the same mistakes you do. I often put the wrong word in when typing quickly, or edit the middle of a sentence forgetting to fix the overall context. Errors are not just due to proficiency in language, but also due to typing skills or low points in attention (pre-morning caffeine).

The thing is, most people will forgive minor mess-ups if it's clear what you actually meant. It's not something to worry about in internet commentary, which is more like an informal chat than formal writing. If you were writing a scientific paper or a politician's speech, this is the time to be concerned about the formal structure and specifics of what's going on.

Edit: it's not to say don't try, just to say don't beat yourself up over small mistakes.