I've seen so many people give out that (bad) advice, to "keep handling sessions short"...It's just wrong. Some snakes seem to pick up on our moods too...when we relax, so do they. If you're not relaxed in 5 minutes, how can you expect a snake to be?
I'm not saying to keep them out all day...& you always need to consider the (room) temperature+ the size & kind of snake...we are roughly 98.6* of heat, so smaller snakes can over-heat if handled by us for too long, especially if it's something like a corn snake that prefers to be 75*. BPs, boas & pythons at least like (need) the warmer temperatures, so handling is usually a "win" for them, as long as it's not forever. If a snake is calm for a while, then gets really restless, that's telling you something, like maybe it's just too warm. Don't take it personal.