Everyone in the software field has seen a parade of patents which do nothing but try to claim rights on techniques that have already been in use for years, let alone developments that while new, are are still obvious to those of us with ordinary skills in programming.
Although this debasement is quite enough to ruin the integrity of software patents, there are some other debasements worth mentioning too. Patents were originally created with a limited time in mind - the 1623 law placed them at fourteen years. This, of course, at a period of time when change was much slower than it is now, let alone than it is in our field. Proper software patents should hold for a shorter period than that.