If your bar chart has faint white lines running through it, like in the below screenshot, its because your Results table is at a more fine grain than your visualisation.
These lines appear because Omni is technically plotting each each row of your table as an individual series in the visualisation, and these thin white lines are the boundaries between these series.
You can easily remove these lines by removing the dimension from your results table that is causing the finer grain and isn’t being plotted. This will make your vis look better, but it will also reduce the probability of you hitting a row limit and accidentally plotting incomplete data.
Check out some examples in this Loom video: Visualizing Data Challenges and Solutions 💡 | Loom