Something positive about Gates for a change. The early IBM PC had a memory limit of 640K, and someone said, or is alleged to have said, "640K of memory ought to be enough for anybody". That person (if there was one) was not however Gates. He has strenuously denied it and I believe him.
Often these falsely claimed quotations originate from journalists looking for a story. Around 1980, when Gates was alleged to have said it, 640K was a lot of memory and it would have been enough for anybody on a PC at that time. There was no software around that could have used it all. Probably someone made a perfectly sensible comment to that effect at that time. Then years later someone dug up the comment and ridiculed it. Assuming that Gates was behind everything to do with the PC, it was attributed it to him.
This is not an entirely positive point though. This myth is tied to the belief that Gates designed the IBM PC (or at least had a hand in it), which he did not. He only sold an operating system for it. The myth over-blows Gates' contribution to computing history.