Or songs that have a 2/4 fill. Or some pop songs which have a few 7/4 measures (actually one 4/4 + one 3/4). Also, a lot of people talk about cueing the first beat, but some tracks start with an upbeat measure at let’s say “3&”. It’s an art to hit play off-beat so the upbeat intro is heard fully while still having the “1” beat line up…
Counting 4/4 isn’t that difficult. But regarding funny 2/4 fills or upbeat measures, starting to play guitar helped me a lot.
And for the real nerds, if you then think you know something about counting and time signatures, start playing in a concert band. By request of my daughter (clarinet), I did on bass. Well, who knew you can encounter 6/4, 5/4, 4/4 and 3/4 all in 5 measures, complete with the necessary ritardando’s, just to encounter 7/8 and 5/8 some measures ahead, etc etc. Tool is for sissies 
But seriously, those are pieces where the difficulty is not playing the notes on your instrument, but rather keeping up with counting and where you are in the score. Following along with counting without playing an instrument is good practice sometimes.
Anyway, all music nerdiness aside, counting is important. It’s one of the few common thing between musicians and DJs, but I know some blazingly fast guitarists who aren’t even able to count properly to 4, and it shows. It’s worth investing some time in this