Why do words with negative connotations have negative connotations?

The human seeks to avoid some things/events, such as this end thing we call "death." It connotes an end; as well, it connotes our being subject to something out of our direct and/or immediate control. I believe it to be in antithesis to what We want--and thus, the "negative connotation." In other Words: We want our way. That all sounds simple enough; sounds like something that we would be o.k. with. Problem however comes when what one sees as something We want is something another sees as something We do not/should not want. Example? Being a friend at the job site/while clocked-in at the job with a co-worker. Result? Discord.