The worst tweet someone can send on twitter is similar to this one:
sorry for all the upcoming tweets! about to enter #twitterchat to LEARN from others!!!!
Other than the excessive use of exclamation marks and the fake gushing about learning (which is an entirely separate post), this tweet is wrong because you should never apologize for your content. (on twitter or anywhere else)
If you’re about to post something and you feel the need to apologize for flooding the stream, then don’t post it.