After reading some of the comments about how Agile is being done elsewhere, I'm pretty pleased with how well it's going where I work. I do wonder why the difference, though.
Standups are 15 minutes (officially) but went longer because we had two scrum teams (called "pods", which name no longer irritates me) working on a project that affected both. We needed the expertise and the resources.
We don't spend a lot of time on backlog grooming, in part because we don't have to split many of our user stories. Things were pretty well broken-down into manageable size when we laid out our work, up front. (Somewhat waterfall-ish, but it has worked out OK.)
Another reason is we have a separate meeting (which we call a "champion meeting" for some reason) where a subset of the whole team identifies uncertainties and determines things that were TBD, if they have to be before the user story can be sized. User stories normally are sized at that time.
We used to use "planning poker" cards, but now people are comfortable singing out their estimates or doubts about the estimates of others, and working to a consensus. If we can't come to a consensus, we'll go with the higher of point estimates.
Teams are small, 5 or 6. (Except for our duo-Pod team, during that project.) About half our people are in St. Louis, the other half are contractors in India. Almost always a St. Louis QA tests what a St. Louis Dev produced, and an India QA tests what an India Dev produced. One BA/scrummaster for the team. (Two, during the duo-Pod project.) Only St. Louis folks attend the "champion meeting", but all attend the daily standup and a weekly coordination meeting (at the end of the India day and the start of the St. Louis day).
Much of the above applies all Pods, some only to the the duo-Pod team, which is breaking up now. Next week, some are going half-time on the duo-Pod work, and then it's just going to be one of the pods.
We've not been slavish in following Agile rules, or our own. The "champion meeting" was added a few months back. And with the end of the duo-Pod, we'll no doubt have to make more changes. We've already started on that.
Why has it gone so well? A couple explanations.
Management had a strong commitment to it, and for the most part hasn't micromanaged it, or even come close. All pods are now on 2-week sprints, and are synchronized, with a 6-2-1 at the end of each quarter. Initially we had a requirement to maintain a somewhat even velocity. If the points accomplished per sprint weren't sufficiently consistent over time, we got "dinged". Now we have to commit to calendar dates for big chunks of functionality, instead, but we get to choose our commitments. (We can't be silly about it, of course.)
We got some training, pretty much from the get-go. Some general Agile training initially, and when we were ready or almost ready for it, more detailed training, like on user story splitting.
Another part is the company culture. There's more of a "fix the problem, not the blame" when things go awry, and the concept of technical debt is understood pretty well, even in the business. (We're about 2 weeks away from removing the last of the Visual FoxPro code from production -- in our Pod's code. We're not quite the first Pod, and won't be the last. So, they know what happens when important-but-not-urgent work is deferred too long.)