Boost contains over 120 libraries and counting, with over 70 authors and maintainers. There are many parts of Boost that I will never use (e.g. most of the pre c++11 libs), but the pros of having it available when you need it far outweigh the cons.
If a particular library is costing you more in compile time than it's worth in convenience, just rm -rf it from your Boost install -- better yet, write a script to prepend `static_assert(false, "this header is banned by decree of vvanders");` to the top of the banned headers.
There's plenty in Boost to love -- don't let a few rotten apples spoil the bunch.
Full disclosure: I'm a Boost developer