Ill play
Id say most of them are typcialy fine for me. Esp if I have the right bike for the job. Though since moving and selling off some of my beaters, I ride less in the rain and snow. So I guess that would be one of them. Another being roads/traffic. I live in a less cycling friendly area than I have in the past, more cars and more highways and no real country to ride out to unless its a long long ride. I never have time for those anymore.
I think the other one a few folks have already mentioned. Life moves on, things change and boy have I lost a good amount of my fitness. That I think would be my biggest with the others as deterrents
But I still can dream!