Question about mental health from wise and experienced software developers

Experience and wisdom are relative things so I would say anybody who has good advice can chime in.

Summary of the problem. I am a software developer with over 10 years of experience in software development. Code quality has been something I am always looking for in a codebase but with the jobs that I have worked, I have observed that in the industry doers are more encouraged, no matter how bad their code is. Also, in the companies I have worked in so far, it seems that code quality is not that big of a deal and in software development, it seems like a topic that gets a lot of theoretical attention but in practice, is not followed so religiously. As a result, my search for such a code base makes me feel frustrated sometimes and I tend to switch jobs, only to be disappointed again.

Regarding my daily tasks, I sometimes have a lot of ideas for improvement but feel that it will have an impact on the time and effort for my task so I purposely switch that part of myself off and just work with whatever is there. This sometimes results in the codebase growing further in the direction I don't want it to.

These thoughts just bug me and I have an itch to re-write the whole thing. However, this is not possible since I work in a team and things have to be delivered in a timely manner.

So, my question is how does someone:

1. Deal with bad code on a day-to-day basis?
2. What approach should be taken to disseminate knowledge to other teammates and make them care about code quality also?
3. How to remain patient and mentally sane and not let these things get to you because you feel you could be doing so much better?
4. Are there actually companies where code quality is part of the policy and not everything is about satisfying customers?