While I appreciate why people would want to abstract around them for some use cases, I gotta point out that nested serial callbacks aren't just a nuisance. 95%ish of the serial cbs I've written in Node have benefited from their nested lexical scoping: A cb in a serial chain tends to rely on results from earlier in the chain, and it's nice to be able to refer to variables in the outer scopes without having to pass hella arguments between callbacks.