Scrum meetings are best kept informal. It's the opportunities to improve that are formally encouraged.
+1 to what Ian said, and I'll add that is very important that the objectives for each Scrum event/meeting be met. The Scrum Guide describes the expected outcomes from each of the events. If you are not reaching those outcomes, then there may be a "leak" in your Scrum implementation that can have bad consequences.
For instance, at one company, they were doing everything Scrummy, except one thing. They failed to invite their stakeholders and customers to their Sprint Reviews. When those stakeholders were finally shown the product after several sprints, the stakeholders cancelled the project immediately. They had a leak, and the leak proved fatal in that case.