As some of the commenters have begun to explain, how to recognise a poem is a very vexed and complex question. Especially now that traditional structures, such as the sonnet or haiku, or rules, such as rhyme schemes, are no longer considered necessary for good and valid poetry.
I will, however, briefly address the sub-questions you pose about something being too "simple" and "without personification" to qualify as poetry. Here is a poem by Ezra Pound called In a Station of the Metro.
The apparition of these faces in the crowd;
Petals on a wet, black bough.
That's it. That's the whole poem. This is clearly "simple" and "lacks personification" yet Pound is considered one of the leading lights of 20th century poetry, someone who purposefully played and experimented with the medium to try and get the effects he desired.
This particular poem - which started much longer before Pound deliberately edited it down to what he saw as its bare essentials - has been called the shortest in the canon. So it's certainly seen as a poem by literary critics, despite its brevity, indicating that neither length nor personification are fundamentals of poetry.