Is there any difference in the emotional intensity by saying "I want to", "I would like to", and "I would love to"? Moreover, which one would be the most appropriate expression when talking to seniors?
"I want to"
Implies demand. Don't use it with your boss at work, unless you do demand or actively strive for something... "I want to win this sales competition" etc
"I would like to", and "I would love to"
Are gradations of just how much you want to.
"I would like to go to the business conference"
"I would love to go to the business conference"
Really? You'd enjoy three days of dull speeches & pep talks that much? No-one will really believe you.
"I would love to go to the football match/rock concert"
Far more believable ;)