The comic efficacy of Homer's personality lies in his frequent bouts of bumbling stupidity, laziness and his explosive anger. He has a low intelligence level and is described by director David Silverman as "creatively brilliant in his stupidity". Homer also shows immense apathy towards work, is overweight, and "is devoted to his stomach". His short attention span is evidenced by his impulsive decisions to engage in various hobbies and enterprises, only to "change ... his mind when things go badly". Homer often spends his evenings drinking Duff Beer at Moe's Tavern, and was shown in the episode "Duffless" (season four, 1993) as a full-blown alcoholic. He is very envious of his neighbors, Ned Flanders and his family, and is easily enraged by Bart. Homer will often strangle Bart on impulse upon Bart angering him (and can also be seen saying one of his catchphrases, "Why you little!") in a cartoonish manner. The first instance of Homer strangling Bart was in the short "Family Portrait". According to Groening, the rule was that Homer could only strangle Bart impulsively, never with premeditation, because doing so "seems sadistic. If we keep it that he's ruled by his impulses, then he can easily switch impulses. So, even though he impulsively wants to strangle Bart, he also gives up fairly easily." Another of the original ideas entertained by Groening was that Homer would "always get his comeuppance or Bart had to strangle him back", but this was dropped. Homer shows no compunction about expressing his rage, and does not attempt to hide his actions from people outside the family.