Git is particularly poor in scenarios such as two people working on the same branch. SVN handles this with ease, but with Git it takes a lot of coordination amongst both contributors to keep things working.
Think fractally. The farther you get from master, the smaller and more atomic each commit should be.
If your merges are taking lots of coordination or failing to auto-merge, you probably have some poor engineering hygeine at play. Every time I've had merge fails, it's due to haste/sloppiness or a dev branch diverging too much from a mainline.