Someone needs to take Trump's twitter account away from him. It is unfair of him to be picking on specific businesses. He can make their stock prices tumble just by sending a tweet. It is too easy for him to send a tweet in the middle of the night without thinking through the consequences.
I don't think Trumps tweets will come back to haunt him. Most of the things he said during his campaign were well thought and if he made promises hi is ready to keep them. Sanders bringing oversized tweet is just a way to manipulate Trump. Trump will definitely veto any legislation that aims at cutting Medicaid, Medicare and Social Security.
Nothing can haunt you if you don't care about anything. Trump has never held public office, I don't think he understands the responsibility on his shoulders. He's just going to keep on tweeting throughout his Presidency without understanding the consequences of his actions. Besides, he's going to be the President, he's just going to use that title to deflect any criticism for the rest of his life.
Firstly, tweets are just small snippets which can easily be misinterpreted. Secondly, tweets are usually short-lived and forgotten quickly. Most likely Mr. Trump will have many more statements and actions, that will have a greater impact in the media, in the future. Unless his comments are extreme, they will most likely be forgotten in short order.