What is the difference between complacency and condescension?

Solution 1:

I don't see the words as being extremely similar.

Smug is exhibiting or feeling great or offensive satisfaction with oneself or with one's situation; self-righteously complacent, where synonyms are self-satisfied, superior, complacent, conceited, self-righteous, holier-than-thou, priggish, self-opinionated. The stress is on the self-righteous attitude accompanying being pleased with oneself.

While I know that complacent means satisfied with how things are and not wanting to change them, I think the connotation is one of unawareness of actual dangers or deficiencies in oneself or something one is a member of, for example, a political party or a church

I think, for example, that much of the world has become complacent about AIDS. We just don't worry about it as we once did.

Condescending means showing or characterized by a patronizing or superior attitude toward others, showing that you believe you are more intelligent or better than other people.

Solution 2:

Complacency is an internal sense of smugness. You can be complacent without involving other people. Condescension is an external sense of smugness. You can only be condescending towards other people.