In the detox I was in this past July we had some older 'know-it-all' folk, but they were the alcoholics. So on top of them thinking they were cool for being able to recite all of the AA sayings at the voluntary AA meetings that were held there, and claiming they would be fine once they got out since they said they had some significant clean time before (which I would hope so since they were like 50) so it was just a matter of detoxing and then putting what they knew into practice, but they were even worse in that they felt superior to the heroin users because 'all they did was drink, never put a needle in their veins, etc...'
In that detox very few people were accepted into the rehab downstairs due to insurance reasons, so the case workers were all struggling trying to get some decent aftercare put in place for the rest of the people. Just about every one of the older alcoholics said they were fine and didn't need rehab and that their aftercare plan was to return to their sober house, meet with their sponsor, and do their '90-in90' [90 meetings in 90 days]. That obviously didn't work for them before, but they were pretty set in their ways and the counselor so there knew that so didn't waste their time trying to convince them to go to rehab if they didn't want to.
Now when I was younger (19) I was in rehab and there were some older heroin addicts there who had it all figured out as well. There were AA/NA meetings there everyday and most of the time the patients were the speakers since we could only get legit speakers from the outside on the weekends. I thought it was pretty stupid to have the patients up there preaching sobriety to everyone else when we all had less than a month clean, and all of that time was from being locked inside a rehab in the middle of nowhere in the dead of winter, so they didn't have any legit 'strength and hope' to share with their experiences when the speakers are supposed to share all 3. But some dudes preached like they were giving a sermon in church while celebrating 20 years clean when in reality it was 20 days clean, or more like zero since some of them were on 200mg of methadone still on top of other comfort meds, ha.