It does impact how you write, and possibly your ability to write, but not always in a predictable or positive sense.
At first it might seem that it's easier to write about a particular emotion when you're experiencing that emotion. Not necessarily. Let's assume that you can somehow work yourself into that emotional state without it seeming strained or artificial. (I'm glossing over that, but recognize the ability to do so is remarkably difficult unto itself.) Does that really give you any value when it comes to portraying that emotion?
For first-person stories, perhaps, but even then it will require significant editing. People undergoing an intense emotion tend to get wrapped up in that emotion, but you don't want that kind of directionless anger, depression, or what have you in a story. There should be enough to get a sense of it, but getting lost in it means you run the risk of losing the narrative, and therefore the reader's attention.
In third-person I'd say it's almost useless. Unless you're going to let the character's thoughts take over the narrative in some subtle way, there's no point. You need to remain firmly in the mind of the narrator, even if your third-person story follows characters (or possibly just one character) closely.
That said, it is helpful when it comes to writing about intense emotion to have experienced that emotion, but the key here lies in past tense. It's hard to describe something when you're currently experiencing it, but far easier when it's a memory. After all, intense emotion is more often than not an inhibitor of logical thinking, which isn't very helpful when you need to sit down and pump out a story.