Somehow people start in that route even though it should be obvious not to.

Nicotine provides a short term mental stimulus that’s great for people who feel exhausted or have trouble staying focused.

That’s why lots of people start smoking in school and lots of professionals continue smoking well past the point at which the health effects are obvious.

I know a pulmonologist who smoked until he was in his thirties. Literally “how do you expect me to do my job without this?” was his response when I pressed him on it. Lawyers still smoke like chimneys and for the same reasons