No explanation for shirtlessness. None. There's gotta be a reason. Tell me, past me. LET ME SEE THE WORLD THROUGH YOUR EYES.
The self hypnosis thing wasn't meant to be taken seriously, but some people took it very seriously and were concerned about the friendship of Elliot and Tedd because of it.
I... I just thought it was funny... *Sniff*
In any case, Elliot takes serious stuff in stride. It's everyday social stuff that'll freak him out.