Whenever you want to imply that something is "good," but also kind of "meh," you can use 还 (hái) in front of the "good" adjective.
Besides expressing continuation, 还 (hái) can also be used to weaken positive adjectives. Used with the adjective "good," this is similar to saying "fairly good" or "pretty good" in English. It's also sometimes used by a speaker to be more modest. Below are some of the most common adjectives that get "toned down" by 还 (hái) in this structure.
Subj. + 还 + 好 / 可以 / 行 / 不错
In this pattern, 好 (hǎo), 可以 (kěyǐ), 行 (xíng), and 不错 (bùcuò) combined with 还 ()hái can all be taken to mean "pretty good" or "all right" or "decent" (but also kind of meh... not great). As in English, intonation and facial expressions help convey the meaning. If expectations were already low to begin with, 还可以 (hái kěyǐ) can have the sense of "pretty darn good;" it all depends on context and tone of voice.