From my own experience I can tell that my addiction to cigarettes has been a big problem. Addiction to alcohol was not strong. I have been drinking for many years and could choose to stop for long periods.
About forty years ago I had about a five years period of enthusiastic use of smoking marihuana mixed with tobacco. I was never hooked to marihuana but to the tobacco mixed.
Once stopped smoking tobacco in the mix and after some time also stopped with use of cannabis with no problem.
Then after some years I tried irregular smoking pure marihuana on and off not hooked.
But then once mixed with tobacco that took me back into a strong tobacco addiction for many years and never had an urge to mix with marhuana again.
For many years I was fighting to no avail stop smoking tobacco and finally stopped tobacco for ten years now without falling back ever again.
All of my friends and relatives who had Covid were vaccinated before, and wearing mask.
I never wearing mask and never took any covid_jab.
As for me, I never got Covid infection.