If you almost exclusively use wikitext, but sometimes make minor fixes (e.g. typos) in VE while previewing, you may not start in the desired mode next time.

Original description:

"Remember last mode" is awful. In fact it is so awful that it has nearly 100% error rate for the majority of users.

VE statistics show that the overwhelming majority of editors use wikitext exclusively or primarily. Lets examine the flowchart for wikitext editors:

1. edit in wikitext mode
2. click to preview
3. if unfinished/unsatisfied then click back to wikitext and continue at 1
4. save

Result: Virtually 100% error rate, except utterly random instances where your last comment was abnormally-saved without previewing.

The WMF's bias towards visual-editor is conflicting with real-world-use by the large majority of editors. Flow triggers continual hostility in users because almost every time we use it we have to stop and repair a mangled post because we started typing wikitext into VE. This is a never ending reminder to hate Flow more, each and every time we're forced to use it.