Point one : with pocket pairs there is usually one way to improve. By hitting 1 of 2 outs left in deck maybe( the outs may of been dealt). With two cards like 2-5 os there are six outs + the runners for straights.
Pocket As and Ks have 5% chance of hitting a partner. The 5-2 os 16 outs for pairs and straights or a 33% chance. Two pair how ever low bet a pocket pair.
If you give a person the right odds they will call with any thing. With pocket pair you need to hit 4 cards to do straight which is even slimmer. Than 2-5 os hitting straight since only 3 verses 4 is more likely to happen.
Lighting strikes the same place quite often if you understand how to handle it. Look at some of the pro's suck outs on TV!