On Friday afternoon, Patti Smith stood on stage at the Englert Theatre and shuffled through papers and books like an absent-minded creative writing teacher in a lecture hall, looking for the right poem to read as she took her glasses off and put them back on, apologizing for being a bit disorganized. She was an endearing presence, like a favorite aunt who always manages to bring the right gift even if it is wrapped haphazardly in yesterday's comics section. On Saturday night, Smith was a commanding stage presence — fierce in one moment, disarmingly charming the next — as she led her powerful band through a career's worth of musical highlights.