Many Agile teams are unaware that there are different techniques for conducting Sprint Retrospectives. I've written up the different techniques available to Agile teams many times. This list is not exhaustive, but here is an overview of four Retro techniques:
4Ls (Liked, Learned, Lacked, Longed For)
This technique is fairly popular because it's easy easy to understand and focuses on facts. Each member of the team shares four topics at the end of the sprint: things they liked, things they learned, things they lacked, and things they longed for. The Longed For topic also allows Retros to be more future-looking. This technique also supports the parsing of positive things (Liked and Learned) and not-so-positive things (Lacked and Longed For) without the value judgement underlying the Problems topic in our current technique.
Start, Stop, Continue
This technique is popular because it's easy to understand. This technique focuses on actions. I like this technique because I think it's the easiest to use for deriving action plans. It also, through the Start topic, helps the Retro be more future-oriented. However, depending on the way people share their items, it can be difficult to determine the emotional state of the team using this technique.
Mad, Sad, Glad
This technique is very popular because it does something a lot of Agile teams like doing during Retros: vent. This technique focuses on emotions. I've used a variant of this technique called Good, Bad, Ugly. While this technique is widely used, I think it's the hardest to use for creating action plans. It is also difficult to be future-oriented using this technique.
Successes, Problems, Opportunities
This technique if fairly well used, and it focuses on events. It is a good technique to use for reviewing the institutional memory of the team. This technique is focused on what happened during the last sprint, but the Opportunities topic can be used to think about the future and possibly create Action Plans.
Some Agile teams do mash ups of these Retro techniques. For example, if the team wants to understand the emotional state of each team member while also facilitating the creation of Action Plans, a team could adopt a Glad, Mad, Start, Stop technique. Regardless of the technique chosen, it is vital that the Development Team is involved in the selection process.