Depends on the country:
In US: Very stressful. And, with the number of Ph.D.s being produced every year by so many universities, the competition is very intense. So some people are stuck doing perpetual "Post-docs." And, even after many years of post-doc, if they get a faculty position, they have to prove themselves worthy of a "tenure". For those who don't know about tenure: Before tenure, you are on probation as a faculty member. You have about 5-7 years to prove your worth to the university that you are able to produce Ph.D., get funding, etc. So, assistant professors have to really slog for the first few years to get their tenures. If you are unsuccessful in securing your tenure, you are asked to leave the university, which can be very embarrassing. And, life is tough especially in basic sciences because it is very hard to find a job outside academia after a Ph.D. in basic sciences.
In India: In institutes like IIT, it completely depends on you. There is no stress of tenure. But, then you have to deal with students and politics in India. There is a little bit of stress of making a complete fool out of yourself in front of the students. Sometimes, students can be extremely disrespectful and make false accusations which can be hard to swallow when you do nothing but wish well for them.