Sometimes a layout doesn't look great for all the different variations in data it will have.
Say you have a style set for the headings on a particular type of page, like a product page.
For almost all products, it looks great the way you have it.
But theres one product page where the heading is too long and causes an ugly line-break to occur. You cannot rename it to something smaller either.
At this point you have 3 options:
Do nothing, just deal with it.
Change the font-size for all product page headings.
Change the font-size on a case by case bases when its too long for one line.
The bad thing about option 1 is most look great but some look awkward.
The bad thing about option 2 is you are degrading the look of all the pages (granted marginally, but still degrading) just to accomadate a few, seems like there should be a better way?
The bad thing about option 3 is the font size is not consistent, creating a less uniform look. Also this can get out of hand, like using inline styles, if you do this too much (or at all) it can lead to a real maintenance nightmare.
So whats the ideal choice? Is there an option I left out?