Is there a formal test determining whether a verb is stative? For example, the following predicate looks stative, but it's not:
It's Valentine's Day. I have the chocolate, but I'm still missing the flowers.
You either are missing the flowers, or you're not. Also, there is no action involved. There is no degree to which you can be missing the flowers. Does not that imply that the verb is stative? How does one account for such cases?
MISS is one of those verbs Yellow Sky alludes to which changes its sense in the progressive: in other casts it ordinarily means regret the absence of, but in the progressive it takes the sense lack (or in the intransitive be lacking). The progressive might better be understood as copular BE + adjective missing.
But there are a number of tests for stativity. Some have been questioned as really involving agency, not stativity, but here are a couple of fairly robust ones:
When employed in a main clause modified by a perfective when clause, events are understood to follow what is described in the when clause; states are understood to start before and continue during what is described in the when clause.
When I met John he bought the flowers.
When I met John he was missing the flowers.
Events can serve as the complement in Wh- cleft constructions; statives cannot.
What John did was buy the flowers.
∗ What John did was be missing the flowers.
Your example is ambiguous. "I'm still missing the flowers" has a literal reading, "My heart still yearns for the flowers of yesteryear", and an idiomatic reading, "In rechecking the inventory of items supposed to be present, I find that the flowers are still absent." I doubt that "missing" in the idiomatic reading is really a progressive form -- it has the sense of the adjective "missing".
The literal reading is non-stative. It refers to what could be a long process: I miss more and more those flowers I used to get.
The simplest way to determine whether a verb is stative is to see if you can use that verb in a Continuous (aka Progressive) tense. If you cannot, then it is a stative verb. Since in your sentence the verb is in the Present Continous tense, the verb to miss is not stative, it is dynamic.
If 'stative' is a binary term, then the only stative verb is 'to be'. Lack of progression has nothing to do with it (states are not required to be permanent). Verbs like 'seem' are control verbs (He seems [to be] odd.) If you want to differentiate events with obvious action (He kissed her) from events with hidden action (He loved her; [the network in his brain formed the pattern that expressed love]), then 'stative' is a weak term for the latter.
