(If you are not able to read the content, rest be assured, it is not due to the photo quality, thanks to Harshit for the photo)
The title says it all, do not dump so much text on a slide that it becomes unreadable to the readers. If the purpose of the slide is to show enabling text to the readers (and supporting/cueing text to the presenter) then this goal is lost in most of the presentations that you will see. People tend to cram as much text as possible on a given slide,
“I have only 15 slides!”
But the person doesn’t mention that 8 of those slides have texts which are not readable with 10 bullet points. A particular feature in slide creating softwares (both Free and proprietary) further aids in this by automatically reducing the text size if it exceeds its standard text box. LaTeX based Beamer will just make your text go below the slide, warning you that this might not be readable, use another slide.
Be responsible, keep less text on each slide, make more slides instead.