If you are an English teacher, then you have had the chance of dealing with the Present Perfect, a tense that boggles the mind of 99.99% of English learners, and whose existence native speakers are usually unaware of. Getting students to understand why we use it instead of a Simple Past form in explanation that makes sense to us teachers/users of the language is the million-dollar challenge, especially in sentences like these:
I've known my best friend ever since we were in primary school.
I haven't bought another car since I sold the last one four years ago.
The run of the mill explanation is that we use the form "have + past participle" to indicate something started some time in the past and continues till the present moment. The fact is the adverbial phrases already reveal the connection with the past (we know that I met my friend when we were in primary school and that I sold my last car four years ago). The use of the verb tense seems to serve more of a nostalgic function, allowing to quickly flash back to that period, without leaving the current moment. We rewind to that point and come back to where we started in the first place. A taste of both worlds, maybe?