Many good answers are not being accepted because of lazy/jealous posters. If I don't accept an answer, I specify why. Please, mark an appropriate solution the answer as soon as you can.
Accepting an answer is not mandatory; do not feel compelled to accept the first answer you receive. Wait until you receive an answer that answers your question well.
(see the help center)
While it's generally helpful to accept the best answer to your question, it is an entirely voluntary action. Very little harm comes if users don't accept answers to their questions:
questions are considered 'answered' by the system if they have an upvoted answer – regardless of acceptance
the community's voting will ensure that the best answers rise to the top (in theory), and in fact there have been complaints that question authors accept worse answers than the community's choice.
It is of course nice to receive a +15 rep bonus when posting an answer and having it accepted, but it's just that – a bonus. Authors don't owe anyone an explanation as to why they didn't accept a certain answer, although it can be helpful to clarify the question if the answers are missing the mark.
It's certainly not fair to call users who don't accept answers lazy or jealous – just like any other vote, users are entitled to accept (or not) whichever answer they choose.
Please, mark an appropriate solution the answer as soon as you can
This can lead to enabling the Fastest Gun in the West Problem. It is true that a lot of newcomers to stackexchange may ask a question and never accept an answer. However, rushing the process may result in overall decrease in discussion quality. See Robert's point about creating useful collection of info/expert knowledge.