That well known line probably comes from Shakespeare's Merchant of Venice, as in:
All that glisters (glitters) is not gold;Often have you heard that told:Many a man his life hath sold
To me it means don't always believe what you see or hear. Sometimes people don't want the truth, this is especially true in DWI cases.
Lawyers are not supposed to offer promises or guarantees of outcomes and yet many do that in an attempt at selling their services. I can sometimes offer "predictable ranges" based upon what is (the info/ the facts) in front of me but to tell people that something is certain is often impossible without all the discovery (police reports, documents, etc.).
Look at this piece of fruit I recently bought at Tops Market. It looks perfect. A perfect pear. Colors are very attractive, and it even has a fancy little label. When I cut it, it was mealy and horrible.
Fruit is always risky, even those pieces that look amazing. I always caution people to not buy into hype or those lawyers that offer guarantees.