One last time, why do cigarettes increase my focus?

Third time I've asked this because of really ridiculous responses. I'm not smoking weed, I know the difference between tobacco and weed and I'm pretty sure you don't buy weed at a store. I'm not addicted to nicotine and it's not from "withdrawl" I know that for sure. I just get a feeling of enthusiasm and focus, mainly towards music and songwriting, after I smoke a cigarette until the nicotine effect wears off. I don't crave them, and I only smoke maybe 2 or 3 a week unless I'm drinking. This started the very first time I smoked a cig so it's not from a nicotine addiction. Now does anyone have a legitimate response for my question? Why do I feel such more focus on music and songwriting after I smoke a cig until the nicotine effect wears off?