First of all, never "walk the board" or huddle around a chart for your daily stand-up. The meeting is for dependency coordination, not reporting or trend analysis. Staring at a burn-down doesn't help the team coordinate!
Secondly, the goal of a Sprint is to meet the Sprint Goal. If you routinely meet your Sprint Goals with a choppy burn-down, or even if you meet your goals without completing the burn-down, your Sprints are still successful! Less-than-ideal trend lines present opportunities for process improvement, but having an ideal trendline for your burn-down is not the point of Scrum!
Optimize for Flow
You're using the wrong tool for the job. While burn-down charts can be useful for projecting trends for longer Sprints, or provide transparency to stakeholders, it sounds like you're abusing the metric as a way to hold the team accountable to some original forecast.
The daily stand-up isn't really designed as a ceremony to huddle around a burn-down chart. It's really a dependency coordination meeting, and a mini-meeting for the team to plan the day's work.
Instead of focusing on the burn-down chart as your primary metric, try focusing on team coordination instead, which often smoothes the burn-down trend line as a byproduct of improved flow. The general guidance is that a Sprint Backlog Item should be 1/2 to 2 days of effort. Did the team complete the work they expected to complete yesterday? Is the work planned for today blocked by dependencies that weren't completed yesterday? Is there newly-discovered work that needs to be planned, or unplanned work that's eating away at team capacity? Let the team call out those things during the daily stand-up, and try to have everyone walk out of the stand-up with a plan for addressing them during the workday ahead!
When to Address Trend Lines
As a general rule of thumb, a burn-down chart is not generally useful for the Development Team within a Sprint. However, it is often a great trailing metric to identify problems with story sizing, dependency management, and flow. From a Development Team perspective, the best time to talk about burn-downs is probably the Sprint Retrospective.
Work comes in all sizes. However, since work is either done or not-done, a burn-down that flatlines until the end of a Sprint is often an indicator of work items that are too large (e.g. more than 4-16 wall-clock hours each) or a poor (or even missing) continuous integration process. It may also indicate hidden blockers or process problems that aren't being raised in the daily stand-ups or reflected in the team's working agreements.
If you have historically had a smoother burn-down, then the chart can be a useful warning signal of hidden problems. However, if your burn-down has always been late to converge, then it's grist for the mill when the team addresses its planning/estimation or dependency-management processes during the Sprint Retrospective.