For something like the modern intensifier (crazy hot), the old standards extremely, really, very, etc work nicely. For other usages, context would be important. Michelle Bachmann is crazy: deluded, a liar, ignorant.

Mostly, it's about getting past linguistic laziness. Sure, lame/retarded/crazy is easy to grab onto and use, but English is a really versatile language with a lot of words. We can take advantage of that. Down in the second link there are some synonyms offered.