As both an author and a reviewer I know the feelings both of waiting for feedback that seems to take ages (and in the pre-electronic age it could take two years from submission to publication) and of having papers needing review when I have other things that also need doing.
As an author, and especially a new one, your paper is special to you, but once it gets into the system it is just one among dozens, or hundreds. It is an idiosyncracy of the scientific peer review system that reviewers very rarely get paid, or if they do it is nowhere near minimum wage for the time spent. So although the paper was the sole focus of your efforts, probably for weeks or months, harsh reality dictates that the reviewers are not going to drop what they are doing just to pay attention to it. It gets done when there is a gap, and with other pressures on time that might be this week, next week or the week after. Most journals allow aboout a month (some have fast track reviewing for rapid communications), if one reviewer drops out that means two consecutive months, which feels like ages if you are the author.
If it is any comfort, it usually takes a lot less time to recommend rejection of complete rubbish than it does to go through a good paper to make it even better.
Peter