If columns of a table are too narrow to display the full title (e.g. if the column just display icons) just a few characters are shown so it’s impossible to guess what the column is about.
Usually I’d expect to see the full title when hovering over the abbreviated word with the mouse cursor but this is not the case in Home Assistant.
Here is an example from the dashboards table:
I guess this might be an easy fix with a huge usability improvement. 
Don’t forget to vote for your own request.
I agree this is a problem, but I think the solution should be different, not tooltips. Those 2 columns in the table should simply be wider. It’s kind of a bug. The table (and other tables like this) already switches to a different view under specific width, so we don’t need a separate solution for when column title doesn’t fit, we just need to make sure the column minimum width is never less than what the column title needs.
or just word wrap the title.
this happens in more than just title field. it happens on entities in an entity card along with the associated values. A datetime entity is especially impacted. so much so that the entity name and data are pretty much unusable.
So word wrap on most things would be helpful.