It depends where you work. Some places have very low expectations for their programmers. I have heard of places with very high expectations, but I've never work

It depends where you work. Some places have very low expectations for their programmers. I have heard of places with very high expectations, but I've never worked at one yet. I've never felt mentally drained, but on occasion I have felt "keyed up" and I can't stop thinking about an interesting problem even when I go home. That is definitely less than 20% of the days in my 10+ year career though.