I totally agree, as on some occasions I play tournaments on my mobile. And playing say up to 3 tables at once can be a challenge to keep up with. A-lot of times each hand is running into the time bank.Well you never know why people take some time.
Maybe he was playing at several tables, shortly away from his computer or indeed he thought if he should shove or not and thinking if you'd make the call or not to maximize his value.
I doubt people do it to annoy others. 🙂