Arpangel wrote:all I can think of is that my standards aren’t as high as some people’s, and I’m happy if things are good enough, or "OK" for better or worse!
A lot depends on the music. From the little I've heard your music has little to do with any standard reference, so - outside some specific technical standards - it probably does not particularly benefit from any particular modification. If there are no vocals, there no vocals to be buried, so to say.
There still may be technical issues, however - and often is about what you don't hear: for example, if you plant to print to vinyl and your bass simply can't fit the medium. The job of the mastering engineer will be in that case to keep the perceived sound as it is as much as possible, while reducing the low end to something that a stylus can manage.. and in that case, if you don't hear any difference, it will be an unmitigated success and a marvelous achievement on his side!
For more traditional forms, say a singer-songwriter track with acoustic guitar and vocals, there's a lot of references and expectations from the public on how it should sound (whether you like it or not) and that may prompt the mastering engineer to ask you if you really mean it... even if, as I mentioned, not so much.
I’ve heard some great records, and really bad ones as far as technical quality goes, and the bad ones are often by people who should be able to afford the best, and the dodgy sound was definitely not intentional. The outcome sometimes, is so very, very unpredictable.
Bad records have little to do with dodgy sound, they have all to do with dodgy music ;-)