Your question reminds me about one time going on a flight in a turboprop from Hawaii to Oakland. Yes we had lots of gas. We would have been in the low twenties at the time with multiple step climbs. About one third of the way through, the captain decided that we could make the ultimate destination of Vancouver non-stop. As a former FO on long range jets, he insisted that we were guaranteed to have tailwinds as there were always tailwinds on that route.
So we got a reroute to Vancouver and guess what? We ended up for part of the flight with a slight headwind. Fortunately, the weather was good and it was late at night and we were able to barely keep our very close, nearby alternate, but it wasn't exactly comfortable for several hours and fortunately, the winds didn't increase much.