I've got a co-worker who negotiated extra time of when he started here (3 weeks instead of the normal 2). Normally, we get an extra week of vacation after 5 years of employment. Unfortunately, they screwed him out of it because he already had 3 weeks, which is the normal amount for someone with 5 years of tenure. :-(
It's kind of interesting that "negotiated five extra weeks of vacation" turns into "failed to get an extra week vacation for every year, indefinitely". I guess it didn't occur to him (or either side, possibly) to specify the difference?
So if he worked there for 10 years he would have gotten 10 x 3 = 30 weeks holiday, however had he not negotiated he would have gotten 5 x 2 + 5 x 3 = 25 weeks.
I cannot see how you consider that he got a bad deal.