Greg Maddux, who could pitch a complete game with around 80 pitches.
Depending on the pitcher, it could simply mean they are throwing too many pitches and they will either wear down before the season is over or be injured.
Even with the potentially negative aspects, a pitcher with a long streak of throwing over 100 pitches is usually doing something right. A pitcher lit up in the first few innings isn't making it to 100 pitches, and it generally means less work for the bullpen. While efficiency might be preferable, it is hard for a power pitcher that goes deep into games to avoid 100 pitches.
A case in point of a staff ace that consistently had over 100 pitches was Randy Johnson, who had 5 separate streaks of at least 20 consecutive starts with 100+ pitches. His best streak was 37 games from June of 1992 until July of 1993.
(Active) Most consecutive starts with at least 100 pitches:
Felix Hernandez (Mariners) 29
Ricky Romero (Blue Jays) 11
Matt Garza (Rays) 8
Bronson Arroyo (Reds) 7
Johnny Cueto (Reds) 5
David Huff (Indians) 5