I have in the past, but three things put me off doing so now;

Pages where I can spot inconsistencies are often controversial, with long dense discussion pages, edits here are almost impossible beyond trivial details. I dont mind fixing trivia, but not if the actual improvement I think I can make is rejected.

There is a bit of a deletionist crusade to keep some topics small, for example, Ive had interesting trivia about a cameras development process simply deleted. Maybe it is truly for the better, but it is not really that easy to add to the meat of the project, without someone else's approval.

Third, the begging banners really feel a bit gross; I know the size of the endowment, and how long it would be able to sustain the project (forever essentially)... It really feels like the foundation is using the Wikipedia brand to funnel money to irrelevant pet causes. This really puts me off contributing.

I made an edit last year, it immediately got reverted and I got a banner on my user page for vandalism. I complained about that, other people agreed with me but the person who reverted my edits never responded. So there it sits.

I think the "deletionist" tendency is one of the biggest problems with Wikipedia. At least it's the main thing that prevents me from making significant contributions. I say tendency, but maybe it really is more of a crusade. Deletion and rejection definitely seem to be the default "predisposition." I've seen a lot of examples of apparently well meaning contributors being pushed away by the need to establish "notability" for a subject and the expectation that all information must be referenced to a fairly limited number of approved reliable sources. These are norms which have been built over a long period of time so it would be incredibly difficult to change them now.

I've also edited random things in the past. Like inaccuracies in Comp.Sci. topics.

I used to like Wikipedia but I'm changing my mind. One thing amongst many others was seeing some company that competed with the startup I worked in basically introduce marketing material into the site. It just feels like it's too big and there are too many interests that want to distort things. I was surprised to see some article recently removed effectively rewriting history and directing to some alternative version. I just checked again and it's been restored but it just seems like the wild west.

I'd need some serious convincing to restore my trust in it. There are still some good technical/science articles I guess. It kind of sucks that instead of getting more reliable information on the Internet we're trending towards not being to trust anything. It's not clear how we fix this since reliability can not be equal to popularity.

It really feels that way because that's what they're doing. There's a legit non-profit internet encyclopedia barnacled with a bunch of generic left wing political stuff, except the barnacle is bigger than the boat.