What was your first boss when you told yourself : Maybe my build is not good at all? You know like this “skillcheck”

Mine was pretty early on Airidah on expert. First playtrough playing a storm druid (self made never saw any guides or anything) lvl 43 I think and Im really considering to start it over with something else xD. This is weird since Im a veteran Diablo player, last time I struggled like this was in D2R with a fresh start Lighning sorc without “stealth” at Duriel. Like the method : spawn portal make one or 2 shots and die and repeat xD