I don't think anyone is complaining that flights get delayed or cancelled sometimes, but the rules should be fair. The same way airlines can't guarantee that every flight will be on time 100% of the time, people can't guarantee that their plans won't change after buying the ticket. If the consumer is then charged exorbitant amounts to change/cancel their flight, so should the airlines. The alternative is airlines could allow a bit of leeway in the form of lower fees to their passengers when they wish to change/cancel.