Anything is more predictable (reliable ) than another human since we were all endowed with free will. We must all take a chance if we are to ever find an individual that will also wish to have a relationship with us that grows and survives.It's a nice buzz until you've lived with the person & really gotten to know them for awhile.
Then you remember that heroin is much more reliable. lol
However if we succumb to not taking that chance the predictability or reliability of never achieving that approaches 100%
When I was actively an addict I believed that heroin would fill the hole in my soul. It was only after I selfishly quit (did it for my own self) did I find I had the capacity to truly appreciate love. While using I much preferred the cocoon of the buzz and my own company.